Germinal epithelia

No adverse effects were noted in the testes. The results of this study indicate that lead affected spermatozoa after release from the germinal epithelium which was possibly protected from the effects of lead by the blood-testes barrier (Barratt et al. 1989). 

Adult males given 500 mg Zn/kg ration, as ZnS04, for 6 weeks After 3 weeks, spermatogenesis was arrested at the primary spermatocyte stage. After 4 weeks, food consumption declined, forelimb lameness, and swelling in cervical lymph nodes. At 6 weeks, testes showed enlarged lumen and abnormal germinal epithelium. 20... 

Reproductive Effects. Reproductive effects have not been examined in humans after exposure to -hexane. A dominant-lethal test in mice showed no effect on male fertility (Litton Bionetics 1980). No effects were seen on reproductive tissues in male rats after intermediate-duration inhalation exposure at 500 ppm (IRDC 1981) or in either sex of mice after intermediate-duration inhalation exposure to up to 10,000 ppm -hexane (Dunnick et al. 1989 NTP 1991). However, inhalation exposure in male rats to higher concentrations of -hexane showed effects after acute-duration exposure to 5,000 ppm (spermatid and spermatocyte degeneration and exfoliation) and atrophy of testicular germinal epithelium after intermediate-duration exposure to 1,000 ppm (De Martino et al. 1987 Nylen et al. 1989). Testicular atrophy in rats was also noted after intermediate-duration oral exposure at 4,000 mg/kg/day (Krasavage et al. 1980). Similar to -hexane neurotoxicity after inhalation exposure, effects on the testes in rats can be reproduced by oral administration of the w-hexane metabolite 2,5-hexanedione (Chapin et al. 1982 ... 

Testicular histopathology revealed that major early changes after exposure to 1,3-DNB consisted of degeneration of germinal epithelium and sloughing of both spermatocytes and spermatids which in turn resulted in reduced sperm counts and reduced sperm mobility (Blackburn et al. 1988 Evenson etal. 1989b Linder etal. 1988, 1990 Reader etal. 1991). Disrupted spermatogenesis was also evidenced by a decrease in the number of seminiferous tubules in rats treated with 48 mg/kg of... 

Follow-up studies have demonstrated that tm-DNB exerts a direct effect on the germinal epithelium and not through alterations in hypothalamic and pituitary control of gonadal function." No reproductive effects have been reported in humans. 

Testicular atrophy of the germinal epithelium was seen in male rats administered 660 mg/kg by gavage for 90 days. ° A reduction in total circulating white blood cells has also been reported after MBK exposure. ... 

Marked and significant reductions in absolute and relative testes weight and atrophy of testicular germinal epithelium were observed in male rats exposed to 700 ppm 2-hexanone for 11 weeks (Katz et al. 1980). 

Male rats that were given 2-hexanone at 660 mg/kg/day (undiluted) by gavage in a 90-day study were observed to develop atrophy of the germinal epithelium of the testes (Krasavage et al. 1980). However, the statistical significance of this observation was not addressed. 

Oral administration of di(2-ethylhexyl) phthalate at levels of 0, 250, 500 or 1000 mg/kg bw to adult albino rats for 15 days resulted in a significant decrease in sperm count in the epididymus and increased activity of P-glucuronidase, y-GT and lactate dehydrogenase and a decrease in the activity of acid phosphatase in the testes. The authors interpreted these findings as indicating germ-cell depletion and deterioration of the germinal epithelium in the testes (Parmar et al, 1986). 

In higher plants, carotenoids are produced in green leaves. In animals, conversion of carotenoids to vitamin A occurs in the intestinal wall. Storage is in the liver also kidney in rat and cat. Target tissues are retina, skin, bone, liver, adrenals, germinal epithelium. Commercial Vitamin A supplements are obtained chemically by extraction of fish liver or synthetically from citral or /3-ionone. 

Much has been said about the positive effects of vitamin E (a-tocopherol) on sexual performance and ability in humans. Unfortunately, there is little scientific rationale to substantiate such claims. The primary reasons for attributing a positive role in sexual performance to vitamin E come from experiments on vitamin E deficiency in laboratory animals. In such experiments the principal manifestation of this deficiency is infertility, although the reasons for this condition differ in males and females. In female rats there is no loss in ability to produce apparently healthy ova, nor is there any defect in the placenta or uterus. However, fetal death occurs shortly after the first week of embryonic life, and fetuses are reabsorbed. This situation can be prevented if vitamin E is administered any time up to day 5 or 6 of embryonic life. In the male rat the earliest observable effect of vitamin E deficiency is immobility of spermatozoa, with subsequent degeneration of the germinal epithelium. Secondary sex organs are not altered and sexual vigor is not diminished, but vigor may decrease if the deficiency continues. 

Reproductive Effects. No studies were found regarding the reproductive toxicity of chlorobenzene in humans. In a two-generation inhalation study, chlorobenzene did not adversely affect various reproductive parameters in rats (Nair et al. 1987). While results of this study suggest reproductive toxicity may not be an area of concern to humans, other considerations are warranted before firm conclusions can be made regarding risk to humans. The slight increase in the occurrence of degeneration of the germinal epithelium of the testes provides some evidence for further... 

In male animals, deficiency results in testicular atrophy, with degeneration of the germinal epithelium of the seminiferous tuhules. This lesion responds to vitamin E or selenium, but not to synthetic antioxidants. 

Reproductive system Parenteral Testis Infertility Necrosis of germinal epithelium... 

Transporters are critical in the function of capillary endothelium, where they contribute to the blood-brain, blood-germinal epithelium (blood-testis and blood-ovary), and blood-placental barriers. Endothelial cells in each of these tissues express high levels of MDR-1. The existence of a blood-brain barrier is well established and is thought to arise... 

A single dose of dichlorvos reportedly damages the germinal epithelium of mouse testes severely (143). 

In 21 boys treated with carmustine or lomustine alone or in combination with procarbazine and vincristine for brain tumors, there were 20 cases of persistent testicular damage (22). From assessment of testicular size it was thought that most of those affected would remain infertile. This supports the idea that germinal epithelium is more susceptible than Leydig cells to cytostatic-induced damage. 

Interference with carbohydrate metabolism in germinal epithelium leading to arrest. . .vat spermatocyte stage (dose related, reversible)... 

H8, Hammar, H., and Hellerstrom, C., Oxygen consumption of the germinal epithelium in psoriatic human skin as measured by the cartesian diver microgasometer. Acla Dermato-Venereol. 48, 563-566 (1968). 

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