Tetrahydrofuran: two-generation reproduction toxicity in Wistar rats by continuous administration in the drinking water.

In a two-generation reproduction toxicity study, 25 male and 25 female Wistar rats per dose group and generation were exposed continuously to tetrahydrofuran in the drinking water for at least 70 days prior to and during mating, gestation, parturition and lactation to weaning, at concentrations of 0, 1000, 3000 or 9000 ppm (approximately 100, 300 and 700 mg/kg/day in males and females premating, 100, 300 and 800 mg/kg/day in females during gestation, and 200, 500 and 1300 mg/kg/day in females during lactation) through two successive generations. In both generations and sexes, water consumption was dose-relatedly reduced at all doses; food consumption and body weight were reduced at 9000 ppm. Necropsy kidney weights were increased in 9000 ppm F0 males. Pup body weight gain during lactation was reduced in both generations (F1 and F2 pups) and eye opening delayed in the first generation (F1 pups) at 9000 ppm; there were no treatment-related malformations. The NOAEL of tetrahydrofuran in drinking water is 9000 ppm for parental fertility and reproductive performance, and 3000 ppm for systemic parental and developmental toxicity.     

Two-generation reproduction study by dosing with glutaraldehyde in the drinking water of CD rats

Adult male and female CD rats (F0) were dosed with glutaraldehyde (GA; CAS number 111-30-8) in drinking water at concentrations of 0 (controls), 50, 250, or 1000 ppm for a 10-wk prebreed period and through mating, gestation, and lactation. Resultant F1 offspring, selected to be parents of the next generation, were continued on the same regime from prebreed through lactation. Twenty-eight parental animals per sex per generation for each dose group were evaluated for clinical signs, body weight (absolute and gain), and water and food consumption. The offspring were evaluated for survival and body weight to weaning. Necropsy and light microscopic examination of removed tissues were conducted in all F0 and F1 parents and in 10 offspring/sex/group/generation. Average daily consumptions of GA (as mean +/- SD) for the low, intermediate, and high concentrations were respectively 4.25 +/- 0.87, 17.50 +/- 4.16, and 69.07 +/- 14.58 mg/kg/d for F0 parental males, and 6.68 +/- 0.78, 28.28 +/- 4.09, and 98.37 +/- 11.71 mg/kg/d for F0 parental females. The corresponding values for the F1 parents were 4.53 +/- 1.02, 21.95 +/- 4.88, and 71.08 +/- 16.21 mg/kg/d for males and 6.72 +/- 0.84, 29.57 +/- 5.41, and 99.56 +/- 16.72 mg/kg/d for females. There were no effects on parental fertility and mating performance or on pup viability and litter size in any generation. No apparent treatment-related histopathology was seen in parents or offspring. Parental body weights and body weight gains were significantly reduced at 1000 ppm at a few isolated time periods, particularly during prebreed. Food consumption was significantly reduced at 1000 ppm for F0 and F1 parents during the prebreed and gestation periods, and at 250 ppm for F0 males during prebreed and gestation and F1 females during gestation and lactation. Water consumption by the F0 and F1 parents of the 250 at 1000 ppm groups was reduced throughout the prebreed period. At 1000 ppm, average litter weights were reduced over lactation d 21-28 for the F1 and F2 offspring. The no-observed-effect level (NOEL) for adult toxicity was 50 ppm and for offspring 250 ppm. There were no indications of reproductive toxicity, and the NOEL for this study was therefore > 1000 ppm.     

Effects of pre- and postnatal exposure to the UV-filter octyl methoxycinnamate (OMC) on the reproductive, auditory and neurological development of rat offspring

Octyl Methoxycinnamate (OMC) is a frequently used UV-filter in sunscreens and other cosmetics. The aim of the present study was to address the potential endocrine disrupting properties of OMC, and to investigate how OMC induced changes in thyroid hormone levels would be related to the neurological development of treated offspring.Groups of 14-18 pregnant Wistar rats were dosed with 0, 500, 750 or 1000 mg OMC/kg bw/day during gestation and lactation. Serum thyroxine (T₄), testosterone, estradiol and progesterone levels were measured in dams and offspring. Anogenital distance, nipple retention, postnatal growth and timing of sexual maturation were assessed. On postnatal day 16, gene expression in prostate and testes, and weight and histopathology of the thyroid gland, liver, adrenals, prostate, testes, epididymis and ovaries were measured. After weaning, offspring were evaluated in a battery of behavioral and neurophysiological tests, including tests of activity, startle response, cognitive and auditory function. In adult animals, reproductive organ weights and semen quality were investigated.Thyroxine (T₄) levels showed a very marked decrease during the dosing period in all dosed dams, but were less severely affected in the offspring. On postnatal day 16, high dose male offspring showed reduced relative prostate and testis weights, and a dose-dependent decrease in testosterone levels. In OMC exposed female offspring, motor activity levels were decreased, while low and high dose males showed improved spatial learning abilities. The observed behavioral changes were probably not mediated solely by early T₄ deficiencies, as the observed effects differed from those seen in other studies of developmental hypothyroxinemia. At eight months of age, sperm counts were reduced in all three OMC-dosed groups, and prostate weights were reduced in the highest dose group. Taken together, these results indicate that perinatal OMC-exposure can affect both the reproductive and neurological development of rat offspring, which may be a cause of concern, as humans are systematically exposed to the compound through usage of sunscreens and other cosmetics.     

Acute and subacute oral toxicity assessment of dry encapsulated and non-encapsulated green coffee fruit extracts

The coffee fruit is a high source of bioactive compounds such as phenolic acids and methylxanthines, comprising chlorogenic acids and caffeine, respectively. Extract from this matrix may be used as supplement or active ingredient of functional foods, energy drinks, cosmetics or drugs. Safety of caffeine- and chlorogenic acid-rich encapsulated and non-encapsulated hydroethanolic extracts from green coffee fruit (GCFE) was assessed by acute and subacute toxicity tests. In the acute test, oral single dosage until 1000 mg/kg per body weight (bw) did not show any adverse effect on both female and male mice according to the Hippocratic screening and clinical parameters for a period of 14 days. While the oral median lethal dose of non-encapsulated GCFE was 5000 mg/kg bw/day, that of encapsulated GCFE was not detectable likely due to the delayed release of caffeine and other compounds from GCFE. Non-encapsulated GCFE displayed a stimulating effect at a dose of 1000 mg/kg bw/day after 30 min of oral administration, but not after 60 min. Daily consumption of encapsulated GCFE for 30 days showed no adverse effect in male rats even at the highest dose. Extrapolating this value of no-observed-adverse-effect level (1000 mg/kg bw/day) to human consumption, a human equivalent dose of 189 mg/kg bw/day or 11.34 g/day could be estimated for encapsulated GCFE considering a 60 kg adult body weight.     

A dose response study following in utero and lactational exposure to di-(2-ethylhexyl) phthalate (DEHP): reproductive effects on adult male offspring rats

The reproductive effects of in utero and lactational exposure to di-(2-ethylhexyl) phthalate (DEHP) in adult male offspring rats were investigated. The selected endpoints included reproductive organ weights, testicular function, hormonal status, sexual behaviour and fertility. Two wide ranges of doses, low and high, were tested. Female Wistar rats were treated daily with DEHP and peanut oil (vehicle control) by gavage from gestation day 6 to lactation day 21. The low-doses were 0.015, 0.045, 0.135, 0.405 and 1.215 mg DEHP/kg body weight (bw)/day, and the high-doses were 5, 15, 45, 135 and 405 mg DEHP/kg bw/day. A reduction in daily sperm production of 19-25% in relation to control was observed in animals exposed to 15, 45, 135 and 405 mg/kg/day. Quantitation of specific cell types shows that the observed effects in daily sperm production are not related to changes in the number of Sertoli cells or their capability to support early stages spermatocytes. A low incidence of cryptorchidism was observed in DEHP exposed groups with a lowest observed adverse effect level of 5mg/kg/day. Serum testosterone concentration was similar to control at most doses but was significantly increased at 0.045, 0.405 and 405 mg DEHP/kg/day. In spite of this effect, the weight of seminal vesicle with coagulating glands was significantly reduced at 405 mg/kg/day. Testis, epididymis and prostate weights were similar among groups. Fertility and sexual behaviour were not affected by DEHP treatment at any dose. Overall, our results show that in utero and lactational DEHP exposure reduces daily sperm production and has the potential to induce reproductive tract abnormalities (of which cryptorchidism seems to be the most sensitive in our rat strain) in male offspring rats. The lowest observed adverse effect levels (LOAELs) for these effects were 15 and 5 mg/kg/day, respectively. Therefore, the no observed adverse effect level (NOAEL) for this study can be set at 1.215 mg/kg/day.     

Toxicological studies on 2,4,6-tribromoanisole

TBA, or 2,4,6-tribromoanisole, is a musty-smelling metabolite of 2,4,6-tribromophenol that is used as a flame retardant and an antifungal agent for wooden pallets and packaging materials. The compound can impart its peculiar, often offensive, odor on product packaging to the concern of consumers for the safety of the package contents. These studies were conducted to evaluate the safety of TBA to humans ingesting products tainted with TBA. In addition to the 28-day oral study, a bacterial reverse mutation study was conducted, and confirmed that TBA was not mutagenic. To evaluate oral safety, TBA was evaluated in single dose and 5-day and 4-week repeated dose oral toxicity studies in rats. The test article, administered in single gavage doses of 2000, 5000 and 7500 mg/kg body weight (bw), in 5 daily repeated doses of 1000, 2000 or 3000 mg/kg bw/day or in 28 daily oral gavage doses of 0 001, 0.01, 100, and 1000 mg/kg bw/day did not result in any deaths. Also, the single and repeat dose studies resulted in no significant differences between control and treated groups on body weight gain, food consumption, clinical observations, blood biochemical values, and hematology findings. Treatment-related adverse findings were only detected in male rats during repeated dose studies and were associated with high plasma concentrations of TBA. The test article-related finding of hyaline droplets in the cortical tubular epithelium of kidneys was associated with increases in α_2μ-globulin content in the kidneys as indicated by the intensity of immunohistochemical staining. These findings were correlated with an increased weight of kidneys in males administered 1000 mg/kg bw/day for 28 days. Chemical induction of hyaline droplets containing α_2μ-globulin in the renal proximal tubule is a process unique to the male rat and is not relevant for human risk assessment. Findings of increased liver weight with minimal centrilobular to diffuse hepatocellular hypertrophy in males treated with TBA at 1000 mg/kg bw/day for 28 days were considered to be an adaptive metabolic response to xenobiotic administration. The increased volume of urine, noted in both males and females treated with 1000 mg/kg bw/day was considered adaptive and necessary to excrete the high xenobiotic burden resulting from TBA administration. TBA appeared to be highly bioavailable since high concentrations of TBA were detected in plasma, at 1, 4 and 8 h after administration of TBA at 100 and 1000 mg/kg bw for 1 and 28 days. Levels were dose-related but did not clarify the course of TBA elimination with time after administration. These studies indicate that TBA, administered orally to rats, produced male rat-specific, treatment-related toxicity at the highest orally administered dose in repeated dose (5-day at 3000 mg/kg bw and 28-day at 1000 mg/kg bw) studies. Therefore, the NOAEL for the 28-day oral study was determined to be 1000 mg/kg bw/day for the rat.     

Two-generation reproduction study in rats given di-isononyl phthalate in the diet

The potential reproductive toxicity of di-isononyl phthalate (DINP: CAS RN 68515-48-0) was assessed in one- and two-generation reproductive toxicity studies. Groups of 30 male and female CRL : CD(SD)BR rats were given DINP via dietary administration at levels of either 0.0, 0.5, 1, or 1.5% (one-generation study) or 0.0, 0.2, 0. 4, or 0.8% (two-generation study). There were no changes in any of the classic reproductive parameters, i.e. mating, male or female fertility, fecundity, gestational index, or length of gestation in either study. The overall NOAELs for these effects were the highest Dietary Level (%)s tested, approximately 500 mg/kg/day in the two-generation study and 1000 mg/kg/day in the one-generation study. There were no testicular effects in parental animals exposed as juveniles and young adults at 960 mg/kg/day in the one-generation study. In the two-generation study, there were no testicular effects in either the P(1) males, exposed as juveniles and young adults or the P(2) (F(1)) offspring exposed in utero, through lactation, and continuously to terminal sacrifice. The NOAEL was 470 mg/kg/day. Offspring survival was reduced at the 1.5% level ( approximately 1100 mg/kg/day) but unaffected at the 1% level ( approximately 760 mg/kg/day). There were decreased offspring body weights both at postnatal day (PND) 0 and during lactation; however, the PND 0 effects were only clearly related to treatment at the 1.5% level. Weights of offspring during lactation were significantly reduced but within the historical control range at Dietary Level (%)s below 1%. As there was rapid recovery at the lower levels, even though treatment continued, the toxicologic significance is unclear. Adult survival was unaffected at any level in either study, but weight gain was significantly reduced at the 1% level ( approximately 600 mg/kg/day). Liver and kidney weights were elevated at Dietary Level (%)s above approximately 110 mg/kg/day, consistent with evidence from other studies of peroxisomal proliferation at these levels. This study showed that DINP treatment does not affect fertility or male reproductive development at doses of up to approximately 1000 mg/kg/day.     

Peri- and postnatal developmental toxicity of the fluoroquinolone antibacterial DW-116 in rats.

DW-116 is a fluoroquinolone antibacterial developed by Dong-Wha Pharmaceutical Industry Co. The aim of this study is to determine the potential adverse effects of this chemical on pregnancy, delivery and lactation of dams and on peri- and postnatal development of F1 offspring. The test chemical was orally administered to pregnant rats from day 16 of pregnancy, through parturition and throughout the period of lactation up to weaning (postnatal day 21) at dose levels of 0, 10, 50, or 250 mg/kg/day. The progeny were examined at birth and subsequently to weaning. Mortality, body weight change, physical signs of postnatal development (pinna detachment, incisor eruption, fur development, eye opening, testis descent and vaginal opening) and behavioral function (righting reflex, negative geotaxis, grip-strength, pupillary reflex, acoustic startle response, rotating rod test, open field test and water-filled T-maze test) were evaluated. When the exposed offspring reached maturity (11 weeks old) their reproductive capacity was assessed. Maternal toxicity was observed only in the highest dose group and was limited to decreased food consumption during the late stage of pregnancy. However, this change was not observed during the lactation period. There were no adverse effects on mortality, clinical signs, body weight, necropsy findings, organ weight of dams in any treatment group. No adverse effects on the offspring were seen with the low and middle doses tested, but the highest dose increased postnatal mortality. The number of stillborn was also increased at the highest dose but the difference was not statistically significant. Meanwhile, no treatment-related effects were observed in clinical sign, developmental and behavioral landmarks and necropsy findings at any dose levels tested. There were no treatment-related effects on the mating of the F1 generation and resulting F2 offspring. The results of this study indicate that the peri- and postnatal administration of DW-116 to female rats results in an increase in postnatal mortality at a minimally maternotoxic dose, i.e., 250 mg/kg/day. Under the experimental conditions, the no-observed-adverse-effect level for peri- and postnatal developmental toxicity was considered to be 50 mg/kg/day.     

Subchronic, reproductive, and developmental toxicity of a fluorotelomer-based urethane polymeric product

A commercial fluorotelomer-based urethane polymeric dispersion, consisting of polymer, surfactant, and water, was evaluated in subchronic, reproduction, and developmental toxicity studies. The dispersion was administered daily by gavage to rats at dosages of 0, 50, 250, or 1000 mg polymer/kg/day or with 70 mg/kg/day of the sulfonate surfactant. Dose levels of 0, 50, 250, or 1000 mg polymer/kg/day were also used for the reproductive and developmental studies. Nasal olfactory epithelial degeneration and necrosis occurred in all dose groups in the 90-day study. Nasal adhesions were observed only in rats administered surfactant alone. Liver-enzyme alterations at 250 and 1000 mg/kg were considered to be potentially adverse effects. The subchronic no-observed-adverse-effects level (NOAEL) was 50 mg/kg. For the reproduction study, rats were dosed for 10 weeks prior to cohabitation and throughout mating, gestation, and lactation. There were no effects on reproductive function in males or females at any dosage. Thyroid weight was decreased in the 250 and 1000 mg/kg day F(1) groups unaccompanied by microscopic effects. In the developmental toxicity study, female rats were dosed from gestation days 6-20; there was no test-substance-related embryolethality, nor was there any dose-related increase in either fetal malformations. Fetal weight was minimally decreased at 1000 mg/kg/day in the presence of slight maternal toxicity; the NOAEL for developmental parameters was 250 mg/kg/day. The polymeric product was not a specific developmental or reproductive toxin.     

Toxicological evaluation of an olive extract,H35: Subchronic toxicity in the rat

The safety of olive extract H35 containing 35% hydroxytyrosol (HT) was tested in a 90-day oral gavage study in Wistar rats. H35 was administered at 0, 345, 691 and 1381 mg/kg bw/day, equivalent to 0, 125, 250 and 500 mg HT/kg bw/day. Reductions in terminal body weight (9%), and a statistically significant reduction in body weight gain (17%, P < 0.05) at week 13 were observed in high dose males, as well as a statistically significant increase in relative weights of the liver, heart, and kidneys of high dose males and females. These changes were not accompanied by pathological or clinical observations and a trend towards reversal was observed in the recovery phase. H35 was well-tolerated and no toxicologically significant treatment-related changes were observed in condition and appearance of rats, neurobehavioral outcomes, motor activity assessments, functional observational battery (FOB), food intake, ophthalmoscopic examinations, hematology, clinical chemistry, urinalysis, necropsy findings, sperm parameters or estrus cycle. The lowest observed adverse effect level (LOAEL) was the 500 mg HT/kg bw/day based on statistically significant reductions in body weight gain and decreased body weight in males. The no observed adverse effect level (NOAEL) was 250 mg HT/kg bw/day, equivalent to 691 mg/kg bw/day of H35 extract.     

Reproductive and developmental toxicity studies of S-1090, cefmatilen hydrochloride hydrate (4)--A study on oral administration during the perinatal and lactation periods in rats

Cefmatilen hydrochloride hydrate (S-1090) was administered daily by gavage to female rats at doses of 100, 300 or 1000 mg potency/kg/day from Day 17 of pregnancy to Day 20 of lactation to assess its effects on pregnant/lactating females and on development of the offspring. In dams, loose feces/reddish brown feces, increased cecum weight, decreased weights of the heart, spleen and submaxillary gland in all the S-1090 dosing groups and a decreased weight of the thymus in the 1000 mg potency/kg dosing group were observed. However, no effects on parturition and lactation were observed in any of the dosing groups. In F1 offspring, although increased cecum weight was found at weaning in all the S-1090 dosing groups, no abnormalities in viability, physical development, sensory functions/reflexes, behavior and reproductive function were observed. No adverse effects were observed in F2 fetuses and offspring. On the basis of these results, the no observed adverse effect levels of S-1090 are estimated to be less than 100 mg potency/kg/day for maternal general toxicity, and 1000 mg potency/kg/day for maternal reproductive toxicity and for developmental and reproductive toxicity in offspring under the conditions of the present study.     

A two generation reproductive toxicity study with curcumin, turmeric yellow, in Wistar rats.

The reproductive toxicity of curcumin, turmeric yellow, in Wistar rats was studied in order to generate additional relevant toxicity information for the use of curcumin in humans by oral administration. The two generation reproduction study was designed and conducted in accordance with OECD Guideline No. 416 [OECD, 1983. Guidelines for Testing of Chemicals, Guideline No. 416. Two Generation Reproduction Toxicity Study, adopted on 26th May 1983] and in compliance with Good Laboratory Practices (OECD, 1997 Principles of Good Laboratory Practice for the Testing of Chemicals. OECD, C(97)186/Final). The curcumin, mixed in the experimental diet at the concentrations of 1500, 3000 and 10,000 ppm was fed to three groups of rats, i.e., low, mid and high dose groups, and studied for two successive generations. A concurrent control group received experimental diet without the curcumin mixture. There were no treatment related adverse toxicological effects in the parental animals. No gross or microscopic changes were observed in any of the organs. None of the reproductive parameters were affected and there were no effects on the offspring other than a small reduction in pre-weaning body weight gain of the F2 pups at the highest dose level. It was concluded that the no observed adverse effect level (NOAEL) for reproductive toxicity of curcumin, fed in the diet for two successive generations to rats in this study was 10,000 ppm, which is equivalent to 847 and 959 mg/kg bodyweight (bw) per day for male rats and 1043 and 1076 for females for F0 and F1 generations, respectively. This study was the final toxicology study on curcumin reviewed by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) at the 61st Meeting, 2003. The JECFA group considered that the small body weight reduction in the F2 pups of the highest dose group prevented this from being regarded as a no adverse effect level, and so allocated an ADI for curcumin of 0-3 mg/kg bw based on the intake of 250-320 mg/kg bw in the mid-dose group as the NOEL.     

Diethylene glycol monobutyl ether (DGBE): two- and thirteen-week oral toxicity studies in Fischer 344 rats.

Standard toxicologic endpoints, supplemented by additional examinations, were studied for groups of 10 Fischer 344 rats/sex given drinking water formulated to supply 0, 50, 250, or 1000 mg diethylene glycol monobutyl ether (DGBE)/kg/day for 13 weeks. These dose levels were based upon initial investigations using drinking water formulated to supply 0, 1000, 1500 or 2000 mg DGBE/kg/day for two weeks. All rats survived the respective treatment intervals with no adverse treatment-related in-life effects, including no alterations in a functional observational battery. In both studies, rats given > or = 1000 mg/kg/day consumed less water and feed and weighed slightly less than controls. For rats given > or = 1000 mg DGBE/kg/day, the liver and red blood cells (RBC) were the primary target organs although the effects were slight. In the 13-week study, rats given 1000 mg/kg/day had statistically significant increased relative liver weight (7-10%) and hepatic cytochrome P450s (24-39%) and UGT (approximately 16%) levels along with slight, statistically significant, decreases in serum total protein, cholesterol and aspartate aminotransferase. Histopathologically, very slight hepatocyte hypertrophy and increased individual hepatocyte degeneration were found in females only. At 1000 mg/kg/day, the RBC count, hemoglobin (Hgb) and hematocrit (Hct) were minimally, but statistically significantly, decreased (5.1-8.7%) but RBC morphology, RBC indices, reticuloctye count and bone marrow and spleen histopathology were unaffected. Absolute and relative kidney weights statistically significantly increased (6-13%) with an equivocal increase in minor histopathologic changes typical of early spontaneous nephropathy. There were no adverse effects on urinalysis, clinical chemistry, sperm parameters or testis histopathology. At 250 mg/kg/day, there were equivocal decreases (approximately 2-3%) in RBC count, Hgb and Hct that were statistically significant for the RBC count and Hgb, but these changes were within the historical control range. This dose level was considered the no adverse effect level (NOAEL).     

Reproductive toxicity studies in rats with rimexolone, a corticoid ophthalmic suspension.

Rimexolone is a potent anti-inflammatory corticosteroid with a lower potential for elevating intraocular pressure, relative to other ophthalmic steroids, and is indicated for postsurgical inflammation and uveitis. Fertility and peri/postnatal toxicities were evaluated at oral gavage doses of 50, 150 or 500 mg/kg, and developmental toxicity at 100, 500, or 1000 mg/kg. In the fertility study, male rats were treated daily beginning 4 weeks prior to mating and females were treated daily beginning 2 weeks prior to mating, and through gestation day 6. Females were necropsied on gestation day 15 and males were necropsied after 10 weeks of exposure. In males, dose-related reductions in mean body weights, body weight gains, and food consumption occurred in all groups. In the 500 mg/kg females, mean body weights were reduced during gestation, and there was an increase in early resorptions and concomitant decrease in viable fetuses at this level. There were no effects on copulation or fertility indices, or on the number of corpora lutea and implantation sites. The no-observed-effect level (NOEL) for fertility and reproductive effects was 150 mg/kg. In the developmental toxicity study, female rats were treated daily from gestation days 6 through 17, necropsied on gestation day 20 and fetuses were evaluated. Maternal toxicity occurred at 500 and 1000 mg/kg as indicated by reduced maternal body weights and body weight gains. However, there was no indication of a developmental effect on fetuses due to rimexolone. The NOEL was 1000 mg/kg for the developing fetuses. In the peri/postnatal toxicity study, female rats were treated daily from gestation day 6 through lactation day 20 and necropsied. F1 developmental and behavioral parameters were evaluated. Selected F1 animals were mated at 12 weeks, allowed to deliver, and necropsied on lactation day 21. At 500 mg/kg, F0 maternal body weights were reduced during gestation and lactation, and F1 pup weights were reduced during lactation and the growth phase. There were no effects on the F1 fertility or reproductive capabilities, or on F2 developmental parameters. The NOEL for the F0 females and F1 offspring was 150 mg/kg. Together, these studies indicate that, unlike some corticosteroids, rimexolone does not produce developmental or reproductive toxicity in rats.     

A dose-response study following in utero and lactational exposure to di(2-ethylhexyl)phthalate: effects on female rat reproductive development.

Phthalates, a class of chemicals used as plasticizers, are economically important due to several industrial applications. Di(2-ethylhexyl)phthalate (DEHP) is the most commonly used phthalate plasticizer, and it has been described as a potent antiandrogen in males. We performed an extensive dose-response study following developmental exposure to DEHP and evaluated the effects on female reproductive development. Two wide ranges of doses that included dose levels relevant for human exposure as well as high doses typically used in toxicological studies were tested. Female Wistar rats were treated daily with DEHP and peanut oil (vehicle control) by gavage from gestation day 6 to lactation day 22. The low doses were 0.015, 0.045, 0.135, 0.405, and 1.215 mg DEHP/kg body weight (bw)/day, and the high doses were 5, 15, 45, 135, and 405 mg DEHP/kg bw/day. At the dose levels tested, no signs of maternal toxicity were observed. A significant delay in the age at vaginal opening (approximately 2 days) at 15 mg DEHP/kg bw/day and above, as well as a trend for a delay in the age at first estrus at 135 and 405 mg DEHP/kg bw/day (approximately 2 days), was observed. Liver enlargement (characteristic of phthalate exposure in rats) was limited to the 135- and 405-mg DEHP/kg bw/day doses. Anogenital distance and nipple development were unaffected. Based on the results of delayed pubertal onset, the no observed adverse effect level for female reproductive development may be set at 5 mg DEHP/kg bw/day.     

Toxicity evaluation of a beta-galactosidase preparation produced by Penicillium multicolor

Tilactase is a beta-galactosidase enzyme preparation having lactase activity produced from the fungus Penicillium multicolor. The safety of tilactase was investigated in rats, dogs, and rabbits. Adult and juvenile rats administered 0, 500, 1000, or 4000 mg/kg bw/day of the enzyme preparation by gavage for 35 days, and dogs administered 0, 200, 500, or 1000 mg/kg bw/day in capsules for 30 days, exhibited no significant dose-related changes in body weights, feed consumption, organ weights, urinalysis, hematological profiles, clinical chemistry, or histopathological profiles. Rats receiving the same doses for 6 months also exhibited no dose-related effects, except for a small increase in the weight of the large intestine, an effect considered to be a physiological reaction to passage of a large amount of a non-absorbable substance. The no-observable-adverse-effect level (NOAEL) was 4000 mg/kg bw/day for rats and 1000 mg/kg bw/day for dogs. In three separate studies to examine reproductive and developmental toxicity, rats received 0, 250, 1000 or 4000 mg/kg bw/day by gavage up to the 7th day of pregnancy, during days 7-17 of pregnancy, and from day 17 of pregnancy to 21 days after delivery. There were no treatment-related effects on the dams, gestation period, numbers of implantations, parturition rates, sex ratios, or survival of offspring in any of the studies. No treatment-related external, internal, or skeletal abnormalities were observed in fetuses from any of the three studies. The NOAEL was 4000 mg/kg bw/day. In addition to the three rat studies, rabbits received 0, 250, 500, or 1000 mg/kg bw/day by gavage from the 6th to 18th day of pregnancy. No treatment-related changes were observed in the dams, or fertility indices; nor were there any treatment-related fetal abnormalities. The NOAEL was 1000 mg/kg bw/day. When viable P. multicolor spores were injected into the tail veins of mice, no deaths occured, no fungal cells were observed in various organs, and histopathology showed only focal necrosis in the liver of some of the animals, including the controls. Similar effects were observed when spores were administered to mice in a single dose by gavage. The particular strain of P. multicolor used to prepare tilactase is not pathogenic.     

Reproductive toxicity evaluation of dietary butyl benzyl phthalate (BBP) in rats

Butyl benzyl phthalate (BBP) was administered in the diet at 0, 750, 3750, and 11,250 ppm ad libitum to 30 rats per sex per dose for two offspring generations, one litter/breeding pair/generation, through weaning of F2 litters. Adult F0 systemic toxicity and adult F1 systemic and reproductive toxicity were present at 11,250 ppm (750 mg/kg per day). At 11,250 ppm, there were reduced F1 and F2 male anogenital distance (AGD) and body weights/litter during lactation, delayed acquisition of puberty in F1 males and females, retention of nipples and areolae in F1 and F2 males, and male reproductive system malformations. At 3750 ppm (250 mg/kg per day), only reduced F1 and F2 offspring male AGD was present. There were no effects on parents or offspring at 750 ppm (50 mg/kg per day). The F1 parental systemic and reproductive toxicity no observable adverse effect level (NOAEL) was 3750 ppm. The offspring toxicity NOAEL was 3750 ppm. The offspring toxicity no observable effect level (NOEL) was 750 ppm, based on the presence of reduced AGD in F1 and F2 males at birth at 3750 ppm, but no effects on reproductive development, structures, or functions.     

One-generation reproductive toxicity study of 2-methylbutane in Sprague-Dawley rats

This study investigated the potential reproductive toxicity of 2-methylbutane in a one-generation reproductive toxicity study using Sprague-Dawley rats. A total of 24 male and female rats per group were given 2-methylbutane by gavage at 0, 100, 300, and 1000 mg/kg/day. Males were dosed for 10 weeks prior to mating and during mating. Females were dosed from 2 weeks before mating to day 21 of lactation. At 1000 mg/kg/day, both genders exhibited an increase in adrenal gland weight, however, a decrease in body weight gain and food intake, an increase in kidney weight, and an increased incidence of histopathological changes of the kidney were also observed in male rats. No treatment-related effects of 2-methylbutane were found in relation to the reproductive capacity of parental animals or the pre- and post-natal development of the F1 generation. There were no treatment-related effects in either gender at ≤ 300 mg/kg/day. Under these experimental conditions, the no-observed-adverse-effect level of 2-methylbutane was 300 mg/kg/day for general toxicity and 1000 mg/kg/day for reproductive capacity and pup development in rats.     

Effects of thalidomide on developmental, peri- and postnatal function in female New Zealand white rabbits and offspring.

The present study determined effects of thalidomide on three successive generations of New Zealand White rabbits after oral dosing to F0 maternal rabbits during the later third of gestation (post major organogenesis) and lactation. One hundred and twenty four time-mated F0 rabbits (31/dose) were gavaged with 0, 30, 150, or 500 mg/kg thalidomide from gestation day 18 (DG 18) to lactation day 28 (DP or day postpartum 28) for approximately 42 days. At 6 months, 12 F1 males and 12 F1 females were randomly paired within each dose group and mated. Reproductive evaluation and/or gross necropsy of the thoracic, abdominal, and pelvic viscera was performed on day 29 postpartum (DP 29) for F0 rabbits, on DP 49 for F1 pups not selected for continued evaluation, after completion of mating for F1 rabbits, and on DG 29 for F1 rabbits on continued evaluation of F2 litter. There was no thalidomide-related mortality in F0 and F1 rabbits. One F0 doe at 30 and 150 mg/kg and 2 at 500 mg/kg aborted. Maternal F0 rabbits had reductions in feed consumption but not body weight gain during the gestation and lactation periods for 150 and 500 mg/kg. The numbers of does with stillborn and all pups dying from DP 1-4 was increased at 150 and 500 mg/kg. Mean number of liveborn (litter size) and percentage of live pups were decreased at 500 mg/kg. A significantly increased number of pups died at 150 and 500 mg/kg, resulting in a reduced viability index and decreased litter size. There were some F1 male and female body weight reductions at 150 and 500 mg/kg postweaning with no change in feed consumption. F1 Caesarean-sectioning and litter observations were normal. Fertility of F1 offspring was not affected by maternal doses of thalidomide, but the pregnancy index may have been reduced by the 500 mg/kg maternal thalidomide dose. There was an apparent dose-related increase in splayed limbs in F1 pups. Splaying has been reported in New Zealand White rabbits and may be a recessive trait. The splay could be caused by the nerve and muscle fiber degeneration and skeletal muscle atrophy observed in some pups. It could also be due to the decrease in litter size, resulting in fewer pups per litter for nursing, leading to rapid weight gain and a failure of the pups to support this weight. No F2 fetal gross external alterations were observed. In summary, pregnant rabbits orally dosed with up to 500 mg/kg thalidomide from gestation day 18 to lactation day 28 had increased abortion, changes in some natural delivery and litter parameters, and limb splay in some F1 pups. No gross external changes were observed in F1 and F2 pups.     

Two-generation reproductive toxicity study of aluminium sulfate in rats

In a two-generation reproductive toxicity study, male and female rats were given aluminium sulfate (AS) in drinking water at 0, 120, 600 or 3000 ppm. AS reduced water consumption in all treatment groups, and body weight was transiently decreased in the 3000 ppm group. In the F1 and F2 pups, preweaning body weight gain was inhibited at 3000 ppm, and the liver and spleen weight was decreased at weaning. At this dose, vaginal opening was slightly delayed. There were no compound-related changes in other reproductive/developmental parameters, including developmental neurobehavioral endpoints. The data indicated that the NOAEL of AS in this two-generation study is 600 ppm for parental systemic toxicity and reproductive/developmental toxicity. The total ingested dose of aluminium from drinking water and food (standard rat diet, containing 25-29 ppm of aluminium) combined for this 600 ppm group was calculated to be 8.06 mg Al/kg bw/day.