Effects of monobutyl and di(n-butyl) phthalate in vitro on steroidogenesis and Leydig cell aggregation in fetal testis explants from the rat: comparison with effects in vivo in the fetal rat and neonatal marmoset and in vitro in the human

BACKGROUND: Certain phthalates can impair Leydig cell distribution and steroidogenesis in the fetal rat in utero, but it is unknown whether similar effects might occur in the human. OBJECTIVES: Our aim in this study was to investigate the effects of di(n-butyl) phthalate (DBP), or its metabolite monobutyl phthalate (MBP), on testosterone production and Leydig cell aggregation (LCA) in fetal testis explants from the rat and human, and to compare the results with in vivo findings for DBP-exposed rats. We also wanted to determine if DBP/MBP affects testosterone production in vivo in the neonatal male marmoset. METHODS: Fetal testis explants obtained from the rat [gestation day (GD)19.5] and from the human (15-19 weeks of gestation) were cultured for 24-48 hr with or without human chorionic gonadotropin (hCG) or 22R-hydroxycholesterol (22R-OH), and with or without DBP/MBP. Pregnant rats and neonatal male marmosets were dosed with 500 mg/kg/day DBP or MBP. RESULTS: Exposure of rats in utero to DBP (500 mg/kg/day) for 48 hr before GD21.5 induced major suppression of intratesticular testosterone levels and cytochrome P450 side chain cleavage enzyme (P450scc) expression; this short-term treatment induced LCA, but was less marked than longer term (GD13.5-20.5) DBP treatment. In vitro, MBP (10(-3) M) did not affect basal or 22R-OH-stimulated testosterone production by fetal rat testis explants but slightly attenuated hCG-stimulated steroidogenesis; MBP induced minor LCA in vitro. None of these parameters were affected in human fetal testis explants cultured with 10(-3) M MBP for up to 48 hr. Because the in vivo effects of DBP/MBP were not reproduced in vitro in the rat, the absence of MBP effects in vitro on fetal human testes is inconclusive. In newborn (Day 2-7) marmosets, administration of a single dose of 500 mg/kg MBP significantly (p = 0.019) suppressed blood testosterone levels 5 hr later. Similar treatment of newborn co-twin male marmosets for 14 days resulted in increased Leydig cell volume per testis (p = 0.011), compared with co-twin controls; this is consistent with MBP-induced inhibition of steroidogenesis followed by compensatory Leydig cell hyperplasia/hypertrophy. CONCLUSIONS: These findings suggest that MBP/DBP suppresses steroidogenesis by fetal-type Leydig cells in primates as in rodents, but this cannot be studied in vitro.     

Human fetal testis xenografts are resistant to phthalate-induced endocrine disruption

Background: In utero exposure to endocrine-disrupting chemicals may contribute to testicular dysgenesis syndrome (TDS), a proposed constellation of increasingly common male reproductive tract abnormalities (including hypospadias, cryptorchidism, hypospermatogenesis, and testicular cancer). Male rats exposed in utero to certain phthalate plasticizers exhibit multinucleated germ cell (MNG) induction and suppressed steroidogenic gene expression and testosterone production in the fetal testis, causing TDS-consistent effects of hypospadias and cryptorchidism. Mice exposed to phthalates in utero exhibit MNG induction only. This disparity in response demonstrates a species-specific sensitivity to phthalate-induced suppression of fetal Leydig cell steroidogenesis. Importantly, ex vivo phthalate exposure of the fetal testis does not recapitulate the species-specific endocrine disruption, demonstrating the need for a new bioassay to assess the human response to phthalates.Objectives: In this study, we aimed to develop and validate a rat and mouse testis xenograft bioassay of phthalate exposure and examine the human fetal testis response.Methods: Fetal rat, mouse, and human testes were xenografted into immunodeficient rodent hosts, and hosts were gavaged with a range of phthalate doses over multiple days. Xenografts were harvested and assessed for histopathology and steroidogenic end points.Results: Consistent with the in utero response, phthalate exposure induced MNG formation in rat and mouse xenografts, but only rats exhibited suppressed steroidogenesis. Across a range of doses, human fetal testis xenografts exhibited MNG induction but were resistant to suppression of steroidogenic gene expression.Conclusions: Phthalate exposure of grafted human fetal testis altered fetal germ cells but did not reduce expression of genes that regulate fetal testosterone biosynthesis.     

Leptin inhibits basal but not gonadotrophin-stimulated testosterone production in the immature mouse and sheep testis

The mechanisms whereby leptin regulates testosterone secretion are complex and are likely to involve actions at different levels of the hypothalamus-pituitary-gonadal axis. In the present study, the effect of leptin on testicular steroidogenesis at different developmental stages in mice and sheep was investigated. Testosterone data from testicular slice and Leydig cells of immature and adult mice testes demonstrated that the action of leptin in the regulation of steroidogenesis appears to be dependent on the developmental stage of the testis. Leptin biphasically modulates basal testosterone production in immature testicular slice cultures: at relatively low concentrations (6.25-12.5 ng mL(-1)) leptin exerts a significant inhibitory effect, but has less of an effect at very low (1.25 ng mL(-1)) or high concentrations (25 ng mL(-1)). However, leptin failed to modulate basal testosterone levels in Leydig cell preparations. In contrast with immature testes, leptin was unable to regulate either basal or human chorionic gonadotrophin (10 IU mL(-1))-stimulated testosterone production in adult testicular slices or Leydig cell cultures. The age- and concentration-dependent regulation pattern was confirmed using sheep testicular slice culture. Leptin (1.56-25 ng mL(-1)) significantly inhibited basal testosterone production in the testis from birth to Day 21, but had no effect on Day 27 or older testes. However, the plasma and testicular concentrations of leptin and testosterone data in the ram indicate that such a regulatory effect of leptin on testis steroidogenesis in vitro is unable to efficiently influence testosterone concentrations in vivo. This does not exclude the possibility of a non-competitive mechanism of interaction between leptin and luteinising hormone to regulate testosterone production. Thus, we hypothesise that leptin is not an important independent regulator of testosterone concentration in the normal physiological state. The physiological significance and mechanism of leptin regulation of basal testosterone production are not known; further studies are required to elucidate these important issues.     

Restraint stress exacerbates alcohol-induced reproductive toxicity in male rats

Cumulative exposure to multiple stresses may lead to aggravating the toxicity of each stress, qualitatively or quantitatively altering biological responses because of toxicological interaction. In this study, we intended to determine the possible effects of restraint stress on reproductive toxicity due to ethanol usage in male rats. Early pubertal male Wistar rats were subjected to either restraint stress (5 h/day) or alcohol intoxication (2 mg/kg body weight) or both for 60 days. Body weights of control and experimental rats were similar during the 60 days of this study. Testes were harvested, weighed, and prepared for enzyme assays, and cauda epididymides were isolated for the determination of density, motility, and viability of stored spermatozoa. Restraint stress or alcohol treatment significantly reduced testis weight and caused significant reductions in steroidogenesis and spermatogenesis. Mean density, motility, and viability of stored spermatozoa were reduced in experimental rats. Plasma testosterone concentrations in rats subjected to restraint stress or alcohol were decreased compared with those of controls, concomitant with increased concentrations of LH and FSH in experimental rats. These data suggest that sub-chronic exposure to restraint stress or alcohol contribute to reduce testicular and epididymal function in exposed rats. The study also suggests that restraint stress exacerbates alcohol-induced reproductive toxicity in rats.     

Relative and combined effects of ethanol and protein deficiency on gonadal function and histology

The aim of the present study is to analyse the relative and combined effects of ethanol and protein deficiency on serum testosterone and LH, and on gonadal histology, in ethanol fed rats. The study was performed in 32 animals divided into four groups, fed with the Lieber & DeCarli control, 36% ethanol, 2% protein, and 36% ethanol 2% protein containing diets, respectively. Two months later, rats were anaesthetized with pentobarbital and sacrificed, and the right testes and epididymus were carefully removed. Both ethanol and protein deficiency independently lead to a decrease in serum testosterone levels, and to testicular atrophy, lowest testosterone levels and highest degrees of atrophy being observed in the rats receiving the 36% ethanol, 2% protein containing diet. Both serum testosterone and testicular size and weight significantly correlated with final weight and serum albumin. Hypospermia, atrophy of the seminiferous tubules, and reduced epididymal diameter were also observed in this last group of animals. Thus, protein deficiency may contribute to hypogonadism of alcoholics.     

Inhibition of Rat and Human Steroidogenesis by Triazole Antifungals

Environmental chemicals that alter steroid production could interfere with male reproductive development and function. Three agricultural antifungal triazoles that are known to modulate expression of cytochrome P450 (CYP) genes and enzymatic activities were tested for effects on steroidogenesis using rat in vivo (triadimefon), rat in vitro (myclobutanil and triadimefon), and human in vitro (myclobutanil, propiconazole, and triadimefon) model systems. Hormone production was measured in testis organ cultures from untreated adult and neonatal rats, following in vitro exposure to 1, 10, or 100 μM of myclobutanil or triadimefon. Myclobutanil and triadimefon reduced media levels of testosterone by 40–68% in the adult and neonatal testis culture, and altered steroid production in a manner that indicated CYP17-hydroxylase/17,20 lyase (CYP17A1) inhibition at the highest concentration tested. Rat to human comparison was explored using the H295R (human adrenal adenocarcinoma) cell line. Following 48 h exposure to myclobutanil, propiconazole, or triadimefon at 1, 3, 10, 30, or 100 μM, there was an overall decrease in estradiol, progesterone, and testosterone by all three triazoles. These data indicate that myclobutanil, propiconazole, and triadimefon are weak inhibitors of testosterone production in vitro. However, in vivo exposure of rats to triazoles resulted in increased serum and intra-testicular testosterone levels. This discordance could be due to higher concentrations of triazoles tested in vitro, and differences within an in vitro model system lacking hepatic metabolism and neuroendocrine control.     

THE EFFECTS OF TREMELLA AURANTIA ON TESTOSTERONE AND CORTICOSTERONE PRODUCTIONS IN NORMAL AND DIABETIC RATS

Tremella aurantia (TA) has been traditionally used as food and crude medicine in Chinese society. The polysaccharide isolated from the fruiting bodies of TA exhibits significant hypoglycemic activity in diabetic mouse models of insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM). Diabetes will cause sexual dysfunction in patients. In the present study, we examined if the treatment of TA on IDDM and NIDDM rats will restore steroidogenesis and then the reproductive function. The fruiting bodies (FB), mycelium (TM) and polysaccharide (GX) of TA were fed to the IDDM and NIDDM rats, and testosterone and corticosterone levels in plasma, the weight of steroidogenic organs, and the expression of steroidogenic acute regulatory (StAR) protein and P450scc enzyme were determined. Plasma testosterone productions were significantly suppressed with the feeding of FB or TM in normal rat (p?<?0.05). Testosterone productions were also significantly suppressed in IDDM diabetes rats (p?<?0.05), and FB or TM could not restore the inhibitory effects (p?>?0.05). There was no significant difference of the testosterone production between normal and NIDDM rats (p?>?0.05). In plasma corticosterone production, there were no differences among control, FB- or TM-fed normal rats (p?>?0.05). Corticosterone levels were reduced in IDDM rats compared to control, and FB or TM could restore its level. Corticosterone levels were induced in NIDDM rats compared to control (p?<?0.05), but FB, TM or GX significantly brought the corticosterone back (p?<?0.05) to the control levels. Considering steroidogenic organs, IDDM rats with or without TA treatments had heavier testis and adrenal glands, but not epididymis, than normal rats with or without TA treatments. There were no effects of TA on the weight of steroidogenic organs among normal and NIDDM rats. However, GX feeding in NIDDM rat had lesser testis weight compared to NIDDM rats. The expression of StAR protein and P450scc enzyme were not different among groups in IDDM and NIDDM rats. Plasma testosterone productions were suppressed in normal rats with the feeding of TA (FB and TM). IDDM rats did have lower testosterone, but not in NIDDM, and FB or TM could not restore the inhibitory effects. The induction of IDDM or NIDDM rats did affect steroidogenesis and steroidogenic organ weights, and the feeding of TA had different effects on steroidogenesis in different types of diabetic rats.     

Effects of maternal exposure to an aromatase inhibitor on sexual behaviour and neurochemical and endocrine aspects of adult male rat

The present study examined the effects of letrozole exposure during brain sexual differentiation on endocrine, behavioural and neurochemical parameters in male rat descendants. Pregnant female rats received 1 mg kg(-1) day(-1) letrozole or vehicle by oral gavage on gestational Days 21 and 22. Exposure to letrozole reduced anogenital distance in males on postnatal Day (PND) 22. At adulthood (PND 75), plasma testosterone levels and hypothalamic dopaminergic activity were increased, but sexual competence was impaired, because fewer successful sexual behaviours (mount, intromission and principally ejaculation) were observed. The impairment of reproductive function by prenatal exposure to an aromatase inhibitor reinforces the importance of adequate oestrogenic activity during perinatal sexual differentiation for complete masculinisation of the hypothalamus.     

Thallium-induced testicular toxicity in the rat

Reproductive tract functions were studied in adult male Wistar rats given 10 ppm thallium as thallium sulfate in the drinking water. After 60 days of treatment, spermatozoa isolated from the cauda epididymides and vas deferens showed reduced motility and immature germ cells were found in the tubular lumen. Histological examination of testes in thallium-treated animals revealed disarrangement of the tubular epithelium and ultrastructural changes in the Sertoli cells with cytoplasmic vacuolation and distension of the smooth endoplasmic reticulum. The activity of testicular beta-glucuronidase was significantly reduced whereas acid phosphatase and sorbitol dehydrogenase activities were unchanged. Plasma testosterone levels were within normal limits. No abnormalities in testicular morphology and biochemistry were seen in animals sacrificed at the end of the first month of thallium exposure. These findings indicate that the male reproductive system is a susceptible target site to toxic effects of thallium under chronic exposure. They also suggest a major involvement of Sertoli cells in the mechanism underlying thallium-induced testicular damage.     

Oxidative status in testis and epididymal sperm parameters after acute and chronic stress by cold-water immersion in the adult rat

Abstract

Stress is associated with detrimental effects on male reproductive function. It is known that stress increases reactive oxygen species (ROS) generation in the male reproductive tract. High ROS levels may be linked to low sperm quality and male infertility. However, it is still not clear if ROS are generated by stress in the testis. The objective of this study was to characterize the role of oxidative stress induced by cold-water immersion stress in the testis of adult male rats and its relation with alterations in cauda epididymal sperm. Adult male rats were exposed to acute stress or chronic stress by cold-water immersion. Rats were sacrificed at 0, 6, 12, and 24 hours immediately following acute stress exposure, and after 20, 40, and 50 days of chronic stress. ROS production increased only at 6 hours post-stress, while the activity and expression of antioxidant enzymes, lipid peroxidation (LPO), and sperm parameters were not modified in the testis. Corticosterone increased immediately after acute stress, whereas testosterone was not modified. After chronic stress, testicular absolute weight decreased; in addition, ROS production and LPO increased at 20, 40, and 50 days. The activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx) decreased throughout the duration of chronic stress and the activity of catalase (CAT) decreased at 40 and 50 days, and increased at 20 days. The expression of copper/zinc superoxide dismutase (SOD1) and CAT were not modified, but the expression of phospholipid hydroperoxide glutathione peroxidase (GPx-4) decreased at 20 days. Motility, viability, and sperm count decreased, while abnormal sperm increased with chronic stress. These results suggest that during acute stress there is a redox state regulation in the testis since no deleterious effect was observed. In contrast, equilibrium redox is lost during chronic stress, with low enzyme activity but without modifying their expression. In addition, corticosterone increased while testosterone decreased, this decrease is related to the negative effects seen in sperm.     

Anti-apoptotic effects of curcumin on cadmium-induced apoptosis in rat testes

Cadmium (Cd) is one of the environmental pollutants affecting various tissues and organs including testis. The aim of this study was to investigate the anti-apoptotic effects of curcumin (Cur) on Cd-induced apoptosis in rat testes. The rats were randomly allotted into one of three experimental groups: control, Cd treated and Cd treated with Cur; each group contained 10 animals. The control group received 2 ml/day of dimethyl sulfoxide (DMSO). To induce toxicity, Cd (1 mg/kg body weight) was dissolved in normal saline and subcutaneously injected into rats for 4 weeks. The rats in Cur-treated group was given a daily dose of 100 mg/kg of Cur for 4 weeks. To date, no examinations of the anti-apoptotic properties of Cur on Cd-induced apoptosis in rat testes have been reported. The mean seminiferous tubule diameter, mean testicular biopsy score values and serum testosterone levels were significantly decreased in Cd-treated groups were compared to the control group. Furthermore, the Cur-treated animals showed an improved histological appearance and serum testosterone levels in Cd-treated group. Our data indicate a significant reduction in the activity of in situ identification of apoptosis using terminal dUTP nick end-labeling in testis tissues of the Cd-treated group with Cur therapy. The present study showed that Cur treatment protected testes against toxic effects of Cd. We believe that further preclinical research into the utility of Cur may indicate its usefulness as a potential treatment on the spermatogenesis after testicular injury caused by Cd-treated rats.     

Effect of nickel sulfate on testicular steroidogenesis in rats during protein restriction

Nickel, a widely used heavy metal, exerts potent toxic effects on peripheral tissues as well as on the reproductive system. Low dietary protein coupled with exposure to this metal induces more severe changes, including biochemical defects, structural disorders, and altered physiologic functions. This study was designed to assess the effects of nickel sulfate on testicular steroidogenesis and to ascertain whether such alterations are reversible with normal protein and protein-restricted dietary regime. Nickel sulfate [2 mg/100 g body weight (bw)] dissolved in double-distilled water was administered on alternate days for 10 doses in a normal protein diet (18% casein) and a protein-restricted diet (5% casein) to Wistar male albino rats (bw 160 +/- 5 g). Two groups, one with a normal protein diet and the other with a protein-restricted diet, served as controls. Twenty-four hours after the last treatment, all the animals except those in withdrawal groups were sacrificed by decapitation. We observed a significant reduction in the activities of the testicular steroidogenic enzymes and plasma testosterone concentration accompanied by a significant elevation in cholesterol and ascorbic acid level in both dietary groups. After 15 days of withdrawal from the nickel sulfate treatment, the testicular steroidogenic enzymes, along with plasma testosterone level, improved significantly in both normal protein-fed and protein-restricted dietary groups. The effects of nickel on testicular cholesterol and ascorbic acid concentration were also reduced after withdrawal. Our results indicate that nickel sulfate affects the steroidogenic enzymes, causing alteration in the formation of testosterone in both dietary groups, which was manifested in the elevated cholesterol and ascorbic acid level with decreased activities of steroidogenic enzymes in adult rats testes. However, these alterations were reversible in both groups of animals fed normal protein diets and protein-restricted diets.     

Cellular and hormonal disruption of fetal testis development in sheep reared on pasture treated with sewage sludge

The purpose of this study was to evaluate whether experimental exposure of pregnant sheep to a mixture of environmental chemicals added to pasture as sewage sludge (n = 9 treated animals) exerted effects on fetal testis development or function; application of sewage sludge was undertaken so as to maximize exposure of the ewes to its contents. Control ewes (n = 9) were reared on pasture treated with an equivalent amount of inorganic nitrogenous fertilizer. Treatment had no effect on body weight of ewes, but it reduced body weight by 12-15% in male (n = 12) and female (n = 8) fetuses on gestation day 110. In treated male fetuses (n = 11), testis weight was significantly reduced (32%), as were the numbers of Sertoli cells (34% reduction), Leydig cells (37% reduction), and gonocytes (44% reduction), compared with control fetuses (n = 8). Fetal blood levels of testosterone and inhibin A were also reduced (36% and 38%, respectively) in treated compared with control fetuses, whereas blood levels of luteinizing hormone and follicle-stimulating hormone were unchanged. Based on immunoexpression of anti-Müllerian hormone, cytochrome P450 side chain cleavage enzyme, and Leydig cell cytoplasmic volume, we conclude that the hormone changes in treated male fetuses probably result from the reduction in somatic cell numbers. This reduction could result from fetal growth restriction in male fetuses and/or from the lowered testosterone action; reduced immunoexpression of alpha-smooth muscle actin in peritubular cells and of androgen receptor in testes of treated animals supports the latter possibility. These findings indicate that exposure of the developing male sheep fetus to real-world mixtures of environmental chemicals can result in major attenuation of testicular development and hormonal function, which may have consequences in adulthood.     

Sustained azoospermia in squirrel monkey, Saimiri sciureus, resulting from a single intratesticular glycerol injection

Previous studies in rats had shown that a single intratesticular injection of glycerol resulted in long-term suppression of spermatogenesis without marked alterations in hormone levels. Studies were undertaken to determine the effect of similar treatment in squirrel monkeys (Saimiri sciureus). Ten monkeys received an intratesticular injection of saline (controls) and ten of glycerol solution (treated). Semen and blood samples were obtained on a weekly or bi-weekly basis one month prior to, during the 8 months following and at 22 months after the injection. Sperm numbers in the semen samples of controls remained at 160-435 x 10(6) per ml throughout the experiment. Sperm numbers in treated animals declined to near zero within two months and remained at zero. Serum testosterone and progesterone levels were not significantly different between control and treated animals. Serum LH and FSH levels were not significantly different between control and treated animals except during months 6-8 after the injection, when levels in the treated were higher. At termination (22 months), the weights and sperm contents of epididymides of the glycerol-treated animals were highly significantly reduced. Steroidogenesis (based on amounts and kinds of steroids formed from 14C-progesterone) by testicular tissue was not altered by the glycerol treatment when measured on a per testis basis. This is the first evidence that a single intratesticular injection of glycerol results in long-term suppression of spermatogenesis in primates, without altering testicular steroidogenesis and serum hormone levels.     

EFFICACY OF INTRAUTERINE INSEMINATION WITHOUT OVARIAN HYPERSTIMULATION FOR MALE OR CERVICAL FACTOR IN WOMEN AGED 40 OR OVER

The aim of this study was to examine effects of photoperiod on the ultrastructure of Leydig cells in rat. For this purpose, 21 male Wistar rats were used. Animals were divided into three groups: Control rats in group I were kept under 12?hrs light: 12?hrs dark conditions (12L: 12D) for 10 weeks. Animals in group II were exposed to long photoperiods (18L: 6D), while rats in group III were exposed to short photoperiods (6L:18D) for 10 weeks. At the end of the experiment, all animals were killed by decapitation and blood samples were obtained. Serum testosterone levels were determined with the use of a chemiluminescent enzyme immunoassay. The testes of all rats were removed and weighed, then processed for light and electron microscopy. For morphometric comparison, diameters of seminiferous tubules in each group were measured. In rats exposed to long photoperiods, testicular weights, diameters of seminiferous tubules and serum testosterone levels were significantly increased as compared to those in control rats, whereas exposure of rats to short photoperiods resulted in a significant decrease of testicular weights, diameters of seminiferous tubules and serum testosterone levels as compared to those in control rats and rats maintained in long photoperiods. The amount of mitochondria and cytoplasmic secretory granules were increased in the cytoplasm of Leydig cells of rats exposed to long photoperiods. Furthermore, an increase in extensiveness of rough endoplasmic reticulum in the cell cytoplasm was noticed in this group, whereas a decrease in mitochondria and cytoplasmic secretory granules of the Leydig cell cytoplasm was seen in rats exposed to short photoperiods. The results of our study indicate that testicular functions increase after exposure to long photoperiods and decrease after exposure to short photoperiods.     

Effects of benzo(a)pyrene on intra-testicular function in F-344 rats

The objective of this study was to evaluate the reproductive risk associated with exposure of adult male Fisher-344 (F-344) rats to inhaled benzo(a)pyrene (BaP), a ubiquitous environmental toxicant present in cigarette smoke, automobile exhaust fumes and industrial emissions. Rats were assigned randomly to a treatment or control group. Treatment consisted of exposure of rats via nose-only inhalation to 75 microg BaP/m3, 4 hours daily for 60 days, while control animals were unexposed (UNC). Blood samples were collected immediately on day 60 of exposures (time 0) and subsequently at 24, 48, and 72 hours, to assess the effect of exposures to BaP on plasma testosterone and luteinizing hormone (LH) concentrations. Mean testis weight, total weight of tubules and total tubular length per paired testes were reduced 33% (P < 0.025), 27% (P < 0.01) and 39%, respectively in exposed rats (P < 0.01) compared with UNC rats. The number of homogenization -resistant spermatids was significantly reduced in BaP-exposed versus UNC rats. Plasma testosterone and intra-testicular testosterone (ITT) concentrations were significantly decreased by BaP compared with those of UNC rats. The decreases in circulating plasma testosterone were accompanied by concomitant increases in plasma LH concentrations in BaP-exposed versus control rats (P < 0.05). These data suggest that 60 days exposure to inhaled BaP contribute to reduced testicular endocrine and spermatogenic functions in exposed rats.     

Effects of Pipecolinomethylhydroxyindane on Testicular and Adrenocortical Function in Rats

Mature and young adult rats were treated with a single dose of 115 mg and 50 mg of pipecolinomethylhydroxyindane (PMHI) maleate per kg of body weight. Large intraperitoneal doses were toxic in mature rats and the growth of younger animals were retarded by the lower subcutaneous dose. In both instances, PMHI caused a rapid reduction in testis weight with arrested spermatogenesis. Atrophic changes to the ventral prostrate and the lowering of blood testosterone levels suggests that the actions of PMHI are not strictly confined to the seminiferous tubules. This was further substantiated by the demonstration of direct inhibition by PMHI of testicular androgenesis in vitro. The actions of PMHI on steroidogenesis may be readily reversible and, compared to tubular actions, are of a minor nature. There were no clear-cut adrenocortical responses to PMHI administration but there was some depression of adrenal gland weight, plasma corticosterone, and aldosterone.     

Reversibility of testicular atrophy induced by Di(2-ethylhexyl) phthalate in rats

Previous studies have shown that di(2-ethylhexyl) phthalate (DEHP) results in atrophy of testes and accessory sex organs accompanied by a decreased testicular concentration of zinc in rats. An experiment was performed to determine whether those changes in rat testes are reversible changes. Young Wistar male rats were administered 2.0 g/kg of DEHP for 14 days. At that time, one-half of the rats were killed for determination of zinc and testosterone concentrations in the testis, liver, and serum, and organ weights. The remaining rats were maintained for additional 45 days without further DEHP administration. Testicular weight of rats administered DEHP over the 14-day period was significantly less than that of the control animals, and testicular testosterone content and zinc concentrations were less than those of the control animals. At the end of the 45-day recovery phase, serum testosterone concentration returned to the control level, but testicular zinc concentration and testosterone content were still lower than those of the control animals. In addition, testicular weight of DEHP-treated rats was lower than that of the control animals and histologically, only a small number of seminiferous tubules showed spermatogenesis. These results indicate that, morphologically, DEHP-induced testicular atrophy appears to be of limited reversibility.     

Acute effects of polychlorinated biphenyl-containing and -free transformer fluids on rat testicular steroidogenesis

Polychlorinated biphenyl (PCB)-based transformer fluids belong to a class of environmentally persistent mixtures with known toxic effects. Here, we studied the acute effects of Askarel (which contains Aroclor 1260) and two substitute transformer fluids (the silicone oil-based DC561 and the mineral oil-based ENOL C) on rat testicular steroidogenesis. Single intraperitoneal (ip; 10 mg/kg body weight) or bilateral intratesticular (itt; 25 microg/testis) injections of Askarel markedly decreased serum androgen levels 24 hr after administration. In acute testicular cultures from these animals, chorionic gonadotropin-stimulated progesterone and androgen productions were severely attenuated. When itt was injected or added in vitro, Askarel inhibited 3ss-hydroxysteroid dehydrogenase (3ssHSD), stimulated 17[alpha]-hydroxylase/lyase (P450c17), and did not affect 17ss-hydroxysteroid dehydrogenase in testicular postmitochondrial fractions. The ip-injected Askarel did not affect 3ssHSD, but inhibited P450c17, suggesting that a more intensive metabolism of peripherally injected Askarel reduces the circulating levels of active ingredients below the threshold needed for inhibition of 3ssHSD and generates a derivative that inhibits P450c17. In contrast to Askarel, itt-injection (25 microg/testis) of DC561 and ENOL C did not affect in vivo and in vitro steroidogenesis. These findings show the acute effects of Askarel, but not silicone and mineral oils, on testicular steroidogenesis.     

Effect of Chronic Ethanol Ingestion on the Structure and Function of Liver, Adrenals and Testes of Male Rats

Ethanol was given as a 15% (v/v) solution in the drinking waterto male rats for 58–108 weeks. There was no evidence oftrue induction of hepatic microsomal enzyme activity nor offatty liver. Biphenyl- and aniline-4-hydroxylase activitieswere increased, however, probably due to enzyme activation resultingfrom removal of bound endogenous substrate by ethanol ratherthan to new enzyme protein synthesis. Treated animals had markedlyenlarged adrenal glands but adrenal histology and serum corticosteronelevels were unaffected. The testes were increased in size andweight but their histological appearance was normal. Plasmatestosterone levels were lower than in controls and plasma LHlevels were markedly elevated. Plasma testosterone protein bindingcapacity was normal. It is postulated that an early effect ofethanol on the testis is to inhibit testosterone synthesis leadingto a compensatory increase in plasma LH secretion and secondarytesticular hypertrophy. The findings are discussed in relationto other experimental studies and their possible relevance tohuman alcoholism.