Effect of vitamin A on hexachlorocyclohexane (HCH) toxicity in the rat.

1. Technical hexachlorocyclohexane (HCH) depleted hepatic stores of vitamin A in male albino rats to cause secondary vitamin A deficiency. 2. Toxicity of HCH in rats is augmented by dietary vitamin A-deficiency as evidenced by growth retardation, organ hypertrophies and alterations in the serum and liver levels of the marker enzymes of toxicity. 3. Supplementation of dietary vitamin A to the rats either in adequate (2000 IU/kg diet) or in an excess but not hypervitaminotic level (10(5) IU/kg diet) resulted in significant protection against the toxicity of HCH. 4. The activities of the hepatic xenobiotic metabolizing enzymes were generally low (with the exception of glutathione S-transferase) in the vitamin A-deficient rats compared to those of the vitamin A supplemented diet groups. 5. The results indicated that dietary vitamin A influences the response of male albino rats to HCH toxicity possibly by modulating the activities of hepatic xenobiotic metabolizing enzymes.     

Dietary antioxidants and the biochemical response to oxidant inhalation: I. Influence of dietary vitamin E on the biochemical effects of nitrogen dioxide exposure in rat lung

Sprague-Dawley rats derived from a specific pathogen-free colony were raised from birth on a test diet containing either 0 or 50 IU vitamin E/kg diet for 8 weeks. Rats from each dietary group were exposed to 3 ppm (5640 μg/m³) nitrogen dioxide (NO₂) continuously for 7 days. They were then killed, and the lungs analyzed for changes in weight, DNA and protein contents, tissue oxygen utilization, sulfhydryl metabolism, and the activities of NADP-reducing enzymes. The difference in dietary vitamin E alone did not cause any significant changes in these parameters. However, after NO₂ exposure the changes in these parameters relative to their corresponding unexposed controls were greater for the deficient rats than for the supplemented rats. The biochemical changes observed may be a response of the lung to injury from NO₂ exposure. The larger changes in the lungs of deficient rats may reflect a greater sensitivity of these animals to inhaled NO₂. The vitamin E contents of lung tissue in deficient and supplemented rats reflected the dietary levels. After NO₂ exposure, the vitamin E content in the lung increased significantly in supplemented rats but decreased in the deficient rats relative to their corresponding unexposed controls. The elevation of vitamin E levels in the lungs of supplemented rats with NO₂ exposure suggests its mobilization from other body sites, whereas in deficient rats this process may not have been possible.     

Motorcycle exhaust induces reproductive toxicity and testicular interleukin-6 in male rats.

Motorcycle exhaust (ME) from two-stroke engines contains many toxicants and poses a potential health hazard. The major objectives of the present study were to investigate the male reproductive toxicity of ME and the underlying mechanisms of toxicity. Male Wistar rats were exposed to ME by inhalation 1 h each in the morning and afternoon, Monday through Friday. Exposures to 1:50 diluted ME for 4 weeks or to 1:10 diluted ME for 2 and 4 weeks showed concentration- and time-dependent decreases of testicular weight, spermatid number, and cauda epididymal sperm number. Subsequent studies were done using 4-week exposure to 1:10 diluted ME. ME caused histopathological changes including testicular spermatocytic necrosis and seminiferous tubule atrophy and cauda epididymal formation of clusters of pyknotic and necrotic sperm cells. ME-exposed male rats mated with untreated females showed decreases of male mating index and female fertility index and an increase of implantation site loss. ME decreased 7-ethoxycoumarin O-deethylase and superoxide dismutase activities but induced proinflammatory cytokine interleukin-6 (IL-6) messenger RNA (mRNA) in the testis. Male rats were exposed to ME with or without cotreatment with 50 mg/kg vitamin E orally for 4 weeks. ME decreased serum testosterone concentration. This effect was reversed by cotreatment with vitamin E. ME decreased testicular spermatid number and induced IL-6 mRNA and protein. These effects were also reversed by the vitamin E cotreatment. The present findings show that ME causes male reproductive effects and induces testicular IL-6 in rats by mechanisms involving induction of oxidative stress and inhibition of steroidogenesis.     

Selenium Ameliorates Ibuprofen Induced Testicular Toxicity by Redox Regulation: Running Head: Se protects against NSAID induced testicular toxicity

Despite the Cox inhibitory anti-inflammatory and antipyretic effects of most widely used non-steroidal anti-inflammatory drugs (NSAIDs), such as Ibuprofen, their chronic use is associated with a plethora of patho-physiological insults. One such toxic effect on testicular tissues is not well studied and the underlying molecular mechanisms remain unexplored. Thus, the current study is designed to evaluate the antioxidant properties of essential trace element selenium (Se) to ameliorative Ibuprofen associated testicular toxic effects. Adult male Wistar rats were divided into 3 groups and fed on diets containing different concentrations of sodium selenite, viz. 0.01 mg/kg (Se- deficient), 0.2 mg/kg (Se-adequate), or 0.5 mg/kg (Se- supplemented) for 8 weeks. After diet feeding schedule, each group was divided into two subgroups i.e., with or without the treatment of Ibuprofen (120 mg/kg Bw). The protective effect of Se was evaluated by measuring testicular Se and selenoproteins status, spermatogenic markers, histopathology and testicular redox status. Ibuprofen diminished seminal volume, sperm count, sperm motility, which correlated well increased testicular reactive oxygen species. Se deficiency exacerbated these detrimental effects of ibuprofen by increasing oxidative stress. Alternatively, Se supplementation through antioxidant enzymes mediated protective effects. Se as essential antioxidant selenoproteins ameliorates Ibuprofen induced male reproductive toxicity.     

Reproductive toxicity assessment of chronic dietary exposure to soy isoflavones in male rats

Epidemiologic and experimental data suggest that consumption of diets that are rich in isoflavones may decrease cancer risk in the breast, prostate, and other tissues. Isoflavones such as genistein and daidzein are structurally similar to endogenous estrogens, and demonstrate both estrogenic and weak anti-estrogenic activities; these activities may underlie the impaired fertility and reproductive tract disorders reported in animals exposed to high doses of isoflavones. To identify possible effects of isoflavones on male fertility, we evaluated reproductive parameters in Wistar-Unilever rats receiving dietary exposure to PTI G-2535, a characterized mixture of soy-derived isoflavones containing 45% genistein, 23% daidzein, and 4% glycitein. Beginning at 10 weeks of age, rats received chronic dietary exposure to the soy isoflavone mixture (200 or 2000 mg/kg diet) for a minimum of 12 months. Controls received unsupplemented chow diet only for the same period. Dietary exposure to isoflavones induced no gross toxicity or alterations in body weight gain. Absolute and relative weights of the testis and epididymis in groups receiving high or low doses of isoflavones were comparable to those of controls, and histopathologic evaluations demonstrated that testicular morphology was similar in all study groups. Isoflavone exposure had no significant effects on spermatid count, sperm production, or sperm morphology in any group. These data suggest that the reproductive system of adult male rats is relatively insensitive to isoflavone toxicity at dose levels that demonstrate significant activity in cancer chemoprevention, and that male reproductive function is unlikely to be affected by long-term administration of isoflavones for cancer prevention or other purposes. The results of this study conducted in adult male rats differ from the significant alterations in reproductive parameters that have been reported in female rats receiving prenatal or juvenile exposure to isoflavones.     

Vitamin K-reversible hypoprothrombinemia in rats. I. Sex differences in the development of hypoprothrombinemia and the effects of beta-lactam antibiotics

Male and female rats were fed an ordinary diet which contained about 500 ng vitamin K/g or a vitamin K-deficient diet containing less than 5 ng vitamin K/g. Hypoprothrombinemic changes such as prolongation of the prothrombin time (PT) and activated partial thromboplastin time (APTT) were detected in male rats within 4-6 days after feeding of the vitamin K deficient diet. Blood clotting factor VII and descarboxy prothrombin (PIVKA) levels changed rapidly, with maximum alteration at 2-4 days. Similar changes in factor VII and PIVKA levels were observed in female rats, but they appeared only after feeding of the K deficient diet for a long period. PT and APTT in female rats showed slight or no alteration even after 10 day feeding of the K-deficient diet. These results indicate that male rats are more susceptible to vitamin K deficiency than female rats. Administration of latamoxef led to a dose-dependent development of hypoprothrombinemia in vitamin K-deficient female rats. The hypoprothrombinemia in vitamin K-deficient female rats was caused by beta-lactam antibiotics with N-methyltetrazolethiol, thiadiazolethiol and methyl-thiadiazolethiol as the 3'-position substituent of the cephem nucleus.     

Reproductive toxicity of di(2-ethylhexyl) phthalate in selenium-supplemented and selenium-deficient rats

Phthalates are abundantly produced plasticizers, and di(ethylhexyl) phthalate (DEHP) is the most widely used derivative in various consumer products and medical devices. Animal studies show that DEHP and various other phthalates cause reproductive and developmental toxicity. Although the evidences are limited, it seems reasonable that DEHP may have a potential for similar adverse effects in humans. Such concerns are increasing, particularly for the developing reproductive system of male infants and children. By taking into account the essentiality of selenium (Se) in testicular structure and functions and the high prevalence of inadequate Se intake in various part of the world, this study was designed to investigate the testicular toxicity of DEHP in Se-deficient male rats and to examine the possible preventive effects of Se supplementation on phthalate toxicity. Se deficiency was generated by feeding 3-week-old Sprague-Dawley rats with a ≤0.05 Se mg/kg diet for 5 weeks. Supplementation groups were on a 1 mg Se/kg diet, and DEHP-treated groups received a 1,000 mg/kg dose by gavage during the last 10 days of the feeding period. Testicular histopathology, sperm count and motility, and sperm morphology were examined, and plasma levels of sex hormones were measured. Toxicity and antiandrogenic effects of DEHP were evidenced by disturbed testicular histology and spermatogenesis, diminished testosterone, leutinizing hormone (LH) and follicle stimulating hormone (FSH) levels, and sperm motility. The effects of DEHP were much more pronounced in Se-deficient rats, whereas Se supplementation was found to be protective, reflecting its regulating role in cellular redox equilibrium.     

Review of testicular toxicity of dinitrophenolic compounds, 2-sec-butyl-4,6-dinitrophenol, 4,6-dinitro-o-cresol and 2,4-dinitrophenol

The present review paper summarizes the data available in the literature concerning dinitrophenolic compounds and evaluates male reproductive toxicity in experimental animals. Gavage and feeding doses of 2-sec-butyl-4,6-dinitrophenol (dinoseb; CAS No. 88-85-7) manifested testicular toxicity, and 4,6-dinitro-o-cresol (DNOC; CAS No. 534-52-1) showed similar but weaker testicular toxicity in laboratory animals. Consecutive doses of dinoseb and DNOC by gavage seemed to induce spermatotoxicity by disturbing spermiogenesis or the maturation process of sperm in the epididymis, and the most probable target cells of spermatotoxicity were thought to be testicular spermatids in rats. Prolonged exposure to dinoseb and DNOC in the diet also induced testicular toxicity in rats. However, the feeding dose of dinoseb irreversibly affected the early stage of spermatogenesis and produced infertility in rats. On the other hand, 2,4-dinitrophenol (DNP; CAS No. 51-28-5) did not show testicular toxicity in laboratory animals according to available literature. Further studies in laboratory animals with nitrophenolic compounds are required for clarification of their testicular toxicity and for risk assessment in humans.     

复合蛋白锌对雄性大鼠生殖系统的影响

目的观察复合蛋白锌 (CPZ)对雄性大鼠生殖系统的影响。方法缺锌饲养大鼠 5周 ,复制缺锌模型 ,再给予CPZ和硫酸锌补锌治疗 4周 ,观察和比较补锌治疗前、后各指标的变化。结果两CPZ剂量组在增加缺锌大鼠血浆及器官锌含量、睾丸重量、精子计数及活力、血浆及睾丸睾酮水平、蛋白质含量等方面显著优于对应剂量的硫酸锌组。结论CPZ能提高和改善雄性大鼠生殖系统的机能活动 ,其疗效显著优于硫酸锌     

Use of Animal Models for Detecting Specific Alterations in Reproduction

Use of Animal Models for Detecting Specific Alterations in Reproduction.Amann, R.P.(1982). Fundam. Appl. Toxicol. 2:13–26. Conventionaltests of reproductive toxicity may fail to detect the effectsof some agents altering reproductive functions in the male orfemale. A valid study of reproductive toxicity must be basedon a sound understanding of the underlying reproductive physiology,use of sensitive and precise analytical methods, a powerfulexperimental design, and evaluation of multiple criteria inboth the male and female. Potential sites and mechanisms ofaction of an agent affecting reproduction were considered togetherwith approaches for tests that might be used. Development ofnew in vitro tests, based on procedures used for probing reproductivephysiology, would be desirable. Procedures for detecting alterationsin male reproductive function using animal models were consideredin detail. For example, spermatogenesis is a long process anda toxic agent may alter functionality of a testicular cell typeseveral days or weeks before this toxicity is detectable asa change in spermatogenesis. Several weeks or months may passbefore a detectable change in semen occurs. Therefore, testsutilizing appropriate animal models should have a duration thatis six times the duration of one cycle of the seminiferous epithelium.Evaluations of male reproductive function would be enhancedby including determinations of testicular spermatid reserves,selected simple but precise and meaningful quantitative evaluationsof testicular histology, determination of the number of spermwithin the distal half of the epididymis, evaluation of theprogressive motility and morphology of sperm from the distalend of the epididymis, and measurement of the concentrationof follicle stimulating hormone in blood. For rabbits, longitudinalanalyses of seminal quality are important.     

Lipoic acid modulates adriamycin-induced testicular toxicity

Adriamycin (ADR), an anthracycline antibiotic, which is widely used as an antineoplastic drug in the treatment of various solid tumors, has been shown to induce reproductive abnormalities in males. In the present study, the effect of lipoic acid (LA) a universal antioxidant was investigated on ADR-induced testicular toxicity in rats. Adult male albino rats of Wistar strain were administered ADR (1mg/kg body weight, i.v.), once a week for 10 weeks. ADR-injected rats showed increased levels of 8-hydroxy-2-deoxyguanosine with high protein carbonyl contents in testicular tissue. These changes were associated with significant increase in DNA damage in the sperm as evidenced by increased single strand breaks in a fluorimetric analysis of DNA unwinding (FADU). The activities of steroidogenic enzymes such as 3beta-hydroxy steroid dehydrogenase and 17beta-hydroxy steroid dehydrogenase, serum testosterone levels were decreased significantly in ADR-treated rats. Flow cytometric evaluation of testicular tissue in ADR-administered rats revealed impaired spermatogenesis and testicular function. Treatment with lipoic acid (35 mg/kg body weight, i.p.) one day prior to ADR administration, maintained near normal steroidogenesis and spermatogenesis, thereby proving it to be an effective cytoprotectant.     

Review of testicular toxicity of dinitrophenolic compounds, 2-sec-butyl-4,6-dinitrophenol, 4,6-dinitro-o-cresol and 2,4-dinitrophenol

The present review paper summarizes the data available in the literature concerning dinitrophenolic compounds and evaluates male reproductive toxicity in experimental animals. Gavage and feeding doses of 2-sec-butyl-4,6-dinitrophenol (dinoseb; CAS No. 88-85-7) manifested testicular toxicity, and 4,6-dinitro-o-cresol (DNOC; CAS No. 534-52-1) showed similar but weaker testicular toxicity in laboratory animals. Consecutive doses of dinoseb and DNOC by gavage seemed to induce spermatotoxicity by disturbing spermiogenesis or the maturation process of sperm in the epididymis, and the most probable target cells of spermatotoxicity were thought to be testicular spermatids in rats. Prolonged exposure to dinoseb and DNOC in the diet also induced testicular toxicity in rats. However, the feeding dose of dinoseb irreversibly affected the early stage of spermatogenesis and produced infertility in rats. On the other hand, 2,4-dinitrophenol (DNP; CAS No. 51-28-5) did not show testicular toxicity in laboratory animals according to available literature. Further studies in laboratory animals with nitrophenolic compounds are required for clarification of their testicular toxicity and for risk assessment in humans.     

Carvedilol alleviates testicular and spermatological damage induced by cisplatin in rats via modulation of oxidative stress and inflammation

The clinical application of the anticancer drug cisplatin is limited by its deleterious side effects, including male reproductive toxicity. In this context, the potential protective effect of carvedilol on testicular and spermatological damage induced by cisplatin in male Sprague–Dawley rats was investigated. Carvedilol was orally administered at a dose of 10 mg/kg for 2 weeks, and cisplatin was given as a single intraperitoneal injection of 10 mg/kg on the 12th day to induce toxicity. Cisplatin significantly reduced reproductive organ weight, sperm count and sperm motility, and increased sperm abnormalities and histopathological damage of testicular tissue. In addition, it resulted in a significant decline in serum testosterone as well as levels of testicular enzymatic and non-enzymatic antioxidants (superoxide dismutase, catalase, glutathione peroxides, and reduced glutathione). Moreover, cisplatin remarkably augmented malondialdehyde, nitric oxide, tumor necrosis factor-α, and nuclear factor-kappa B contents in testicular tissue. Conversely, carvedilol administration markedly mitigated cisplatin-induced testicular and spermatological injury as demonstrated by suppression of oxidative/nitrosative and inflammatory burden, amendment of antioxidant defenses, enhancement of steroidogenesis and spermatogenesis, and mitigation of testicular histopathological damage. The current study reveals a promising protective action of carvedilol against cisplatin-induced reproductive toxicity by virtue of its anti-inflammatory and antioxidant properties.     

Effect of dietary fat-soluble vitamins A and E and proanthocyanidin-rich extract from grape seeds on oxidative DNA damage in rats.

This study reports the effect of the fat-soluble vitamin A or vitamin E and grape seed proanthocyanidin extract (GSPE) on oxidative DNA damage estimated by 8-oxo-7, 8-dihydro-2'-deoxyguanosine (8-oxodG) contents in urine and leukocyte of rats. Little is known about the antioxidant potency of dietary anthocyanidins and consequently, the aim of this study was to establish whether anthocyanidins could act as putative antioxidant micronutrients. Seven groups of male Sprague-Dawley rats were fed during 47 days with the following diets: a basic diet, two deficient vitamin A or E diets, two supplemented vitamin A or E diets and two supplemented diets enriched with two doses of grape seed proanthocyanidin extract. At the end of the diet intervention period, 24h, urine and blood were collected. The levels of 8-oxodG in leukocytes rats were significantly lower in the supplemented vitamin A, E and GSPE diet groups with respect to the control group. However, consumption of alpha-tocopherol, vitamin A or GSPE had no effect on the excretion of the oxidised nucleoside 8-oxodG. These results suggest that a vitamin E and A and GSPE enriched-diets have a protective effect on oxidative DNA damage limited to rat leukocytes.     

Dietary influences on theobromine-induced toxicity in rats

Theobromine-induced toxicity was compared at 8, 16, 21, and/or 28 days in rats given either a semisynthetic diet or a pulverized commercial diet in each of which 0.6 or 0.8% theobromine was incorporated. Rats given the pulverized commercial diet containing theobromine consumed more food and therefore, more theobromine over a 28-day period, and gained more weight than did rats given theobromine incorporated into the semisynthetic diet. Serum theobromine concentrations were significantly higher in rats given 0.8% theobromine in the semisynthetic diet than in rats given 0.8% theobromine in the pulverized commercial diet. Spermatogenic cell degeneration and necrosis in the testes of rats fed 0.8% theobromine in the semisynthetic diet for 16 days seemed to be limited to seminiferous tubular cross sections containing stages X to XIV of spermatogenesis, but after 28 days all tubular cross sections showed extensive spermatogenic cell destruction. No significant pathological changes were observed in the testes of rats fed 0.8% theobromine in the pulverized commercial diet for 21 days; spermatogenic cell degeneration and necrosis and multinucleate cell formation were seen after 28 days in seminiferous tubular cross sections containing the early stages of spermatogenesis, but sections containing stages X to XIV were spared or were much less involved. Atrophy of the thymus gland occurred earlier than testicular damage on each respective dietary regimen containing theobromine and was more severe in rats given theobromine in the semisynthetic diet.     

Chemoprotection of ethylene glycol monoethyl ether-induced reproductive toxicity in male rats by kolaviron, isolated biflavonoid from Garcinia kola seed

The present study investigated the protective effect of kolaviron, a biflavonoid from the seed of Garcinia kola, on ethylene glycol monoethyl ether (EGEE)-induced reproductive toxicity in male rats. The protective effect of kolaviron was validated using vitamin E, a standard antioxidant. EGEE was administered at a dose of 200 mg/kg. Other groups of rats were simultaneously treated with kolaviron (100 and 200 mg/kg) and vitamin E (50 mg/kg) for 14 days. EGEE treatment resulted in significant decrease in glutathione (GSH) level, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities but markedly increased the glutathione-S-transferase (GST) and lactate dehydrogenase (LDH) activities in the testes. In the spermatozoa, administration of EGEE caused significant decrease in the activities of CAT, GPx, GST and LDH as well as in the level of GSH but significantly increased SOD activity with concomitant increase in hydrogen peroxide and malondialdehyde levels in both testes and spermatozoa. EGEE-exposed rats showed marked testicular degeneration with concomitant decrease in spermatozoa quantity and quality. Overall, EGEE causes reproductive dysfunction in rats by altering antioxidant systems in the testes and spermatozoa. Kolaviron or vitamin E exhibited protective effects against EGEE-induced male reproductive toxicity by enhancement of antioxidant status and improvement in spermatozoa quantity and quality.     

Effects of vitamin K-deficient diets and fasting on blood coagulation factors in conventional and germ-free rats

Feeding of vitamin K-deficient diets or fasting produced vitamin K deficient syndromes in both conventional and germ-free male rats in 3 days, increasing prothrombin time (PT), activated partial thromboplastin time (APTT), plasma and liver descarboxyprothrombin (PIVKA) levels and liver gamma-glutamylcarboxylase activities, but decreasing plasma clotting factor VII and prothrombin levels. These changes were not found when daily 30 micrograms/rat of vitamin K1 was injected during this period. The changes caused by fasting were comparable with those caused by a diet containing 20-30 ng/g of vitamin K1, while a diet containing less than 5 ng/g caused greater changes in both conventional and germ-free rats. Germ-free rats on a diet containing sufficient amounts of vitamin K1 showed PT and APTT values similar to those in conventional rats, but lower plasma clotting factor levels and higher PIVKA and microsomal gamma-glutamylcarboxylase activities. The values for PT, APTT, factor VII, prothrombin and PIVKA in the fasted germ-free rats were almost the same as those in the fasted conventional rats. These findings suggest that menaquinones synthesized in the large intestine are not utilized sufficiently to prevent vitamin K deficiency in rats.     

Toxicity of di(2-ethylhexyl)phthalate (DEHP) and di(2-ethylhexyl)adipate (DEHA) under conditions of renal dysfunction induced with folic acid in rats: enhancement of male reproductive toxicity of DEHP is associated with an increase of the mono-derivative

F344 male rats were given five consecutive weekly subcutaneous injections of folic acid for induction of chronic renal dysfunction and then di(2-ethylhexyl)phthalate (DEHP) or di(2-ethylhexyl)adipate (DEHA) in the diet at a concentration of 0, 6000 or 25,000 ppm for 4 weeks in order to investigate whether male reproductive toxicity of the two chemicals might be enhanced under conditions of renal disease. Control animals also received DEHP or DEHA in the same manner but without folic acid pretreatment. Decreased testicular weights, seminiferous atrophy with vacuolization of sertoli cells and diminished sperm counts were more prominent in rats given folic acid and then 25,000 ppm DEHP as compared to those exposed to DEHP alone. No such reproductive toxicity was evident in rats given 6000 ppm DEHP or either dose of DEHA. An increased concentration of the mono-derivative of DEHP (mono(2-ethylhexyl)phthalate, MEHP) in the blood, testis and urine was considered relevant to the enhanced reproductive toxicity observed with DEHP.     

Renal toxicity induced by folic acid is associated with the enhancement of male reproductive toxicity of di(n-butyl)phthalate in rats

Reproductive effects have been observed in experimental animals treated with di(n-butyl)phthalate (DBP), one of phthalate esters used in soft plastics and a variety of consumer products. In this study, we investigated whether testicular toxicity of DBP is influenced by diminished renal function. To generate an experimental condition reflecting chronic renal disease in man, adult male F344 rats were given five consecutive weekly subcutaneous injections of folic acid at a dose of 300 mg/kg and then a diet containing 1200, 5000, and 20,000 ppm of DBP for 4 weeks. These concentrations roughly correspond to 60, 250, and 1000 mg/kg per day per rat, respectively. Folic acid clearly induced interstitial nephritis accompanied by impairment of renal function. Seminiferous degeneration, diminished spermatogenesis and increase in the number of morphologically abnormal sperm were more prominent in rats given folic acid and then 20,000 ppm DBP as compared to those exposed to DBP alone. These data suggest that DBP-induced male reproductive toxicity can be increased by folic acid-induced renal dysfunction.     

Effects of vitamin A deficiency on hepatic and extrahepatic mixed-function oxidase and epoxide-metabolizing enzymes in guinea pig and rabbit.

Male guinea pigs and male rabbits were fed a vitamin A deficient diet for 9 weeks and for 12 weeks respectively. Hepatic levels of vitamin A were significantly reduced in the vitamin A deficient animals. The activities of some xenobiotic-metabolizing enzymes were measured in the liver, lung and small intestine. Aryl hydrocarbon hydroxylase, aniline hydroxylase, and 7-ethoxycoumarin deethylase activities were decreased in the vitamin A deficient guinea pig liver. However, in the guinea pig small intestine, aniline hydroxylase, 7-ethoxycoumarin deethylase, aminopyrine demethylase, and aryl hydrocarbon hydroxylase specific activities were increased. In rabbits, vitamin A deficiency decreased hepatic aniline hydroxylase and 7-ethoxycoumarin deethylase activities but increased intestinal aminopyrine demethylase activity. Enzyme activities in lung were not altered by vitamin A deficiency in guinea pig or rabbit. Microsomal epoxide hydrase and microsomal supernatant glutathione S-transferase activities in the three tissues of both species were not altered by vitamin A deficiency.