Sperm, production

A testosterone microsphere system for treatment of hypogonadol males has been developed and clinically evaluated (61,78). This formulation is based on a glycolide/DL-lactide copolymer and natural testosterone (Fig. 6). Because testosterone is not a very potent compound, about 600 mg of the drug is needed in adult males over a 90-day period. The performance of the testosterone system in baboons is shown in Fig. 7. Similar formulations have also been used in the control of the wild horse population of the western United States. Stallions were injected with a testosterone microsphere formulation designed to inhibit sperm production over a 6-month period (79). 

Decreased libido, decreased energy, erectile dysfunction, impotence, decreased sperm production, infertility, gynecomastia, and rarely, galactorrhea. 

Chowdhury et al. (1986) reported that occupational exposure of 10 men to lead caused a significant decrease in sperm count and motility and an increased percentage of abnormal spermatozoa. The average PbB concentration in the lead-exposed group was higher (42.5 pg/dL) compared to controls (14.8 pg/dL). Assennato et al. (1987) reported decreased sperm production in 39 battery factory workers with high PbB levels ranging from 50 to 61 pg/dL, compared to 39 nonexposed workers. Lerda (1992)... 

There is some evidence from animal studies that cannabis can lead to reduced sperm production and impaired ovulation (Bloch, 1983). Furthermore, it has been reported that prenatal exposure to cannabis leads to significant impairment of... 

Arena AC, Femadez CD, Porto EM et al (2008) Fenvalerate, a pyrethroid insecticide, adversely affects sperm production and storage in male rats. J Toxicol Environ Health A 71 1550-1558... 

Not only is it difficult to detect effects on male fertility because of group-size considerations, effects on male fertility mediated by decreased sperm production are also difficult to detect because of the normally huge excess of sperm included in a rat ejaculate. Sperm production can be decreased by up to 90% without effect on fertility (either pregnancy rate or litter size) in the rat. This is not the case for men, so the sperm excess in the rat represents a serious flaw in the rat model (see Working, 1988). To address this deficiency and improve the sensitivity of the model, it is advisable to determine the effects of the test agent on testes weights, testicular spermatid counts, and histopathology of the testes (preferably plastic sections) in the male fertility study and/or the 14-week toxicity study. In some cases, these parameters may be more predictive of possible effects on male fertility in humans than the fertility rate in rats. 

Neaves, W. B., Johnson, L., Porter, J. C., Parker, C. R. and Petty, C. S. (1984). Leydig cell numbers, daily sperm production, and serum gonadotropin levels in aging men. Journal of Clinical Endocrinology and Metabolism 59, 756-763. 

Radioactivity ( H or "C-1,2-dibromoethane) was detected in spermatozoa collected approximately 1 week following the initial oral dose (Amir 1973). These results indicate that 1,2-dibromoethane exerts spermicidal action during the process of spermiogenesis and sperm maturation. This conclusion was supported by the evidence that the percentage of sperm abnormalities was highest when little 1,2-dibromoethane radioactivity could be detected in sperm. In addition, reduction in sperm concentration was more pronounced in adult bulls than in young bulls, and the period of recovery was longer in adult animals (Amir 1975). In another study, bulls were fed 2 mg/kg/day 1,2-dibromoethane for 12 months followed by 4 mg/kg 1,2-dibromoethane every other day until they reached the age of 14-16 months. The semen samples examined revealed low sperm density, structural abnormalities, and low mobility (Amir and Volcani 1965). Sperm production returned to normal as early as 10 days postexposure (Amir and Lavon 1976 Amir et al. 1977). 

The reproductive systems of both males and females can be harmed by particular chemicals. In males certain chemicals cause the testes to atrophy and reduce or eliminate their capacity to produce sperm. Particularly striking in this regard is a now banned but once widely used pesticide called DBCP, residues of which persist in ground water supplies in a few regions of the country. Its pronounced impact on spermatogenesis is readily detectable in experimental animals and, unfortunately, has also been observed in some men once occupation-ally exposed to large amounts. The heavy metal cadmium is another substance effective at reducing sperm production. 

De Fraipont, M. and Sorensen, P. W. (1993). Exposure to the pheromone 17cc,20 /3-dihydroxy-4-pregnen-3-one enhances the behavioral spawning success, sperm production and sperm motility of male golddsh. Animal Behaviour 46,245-256. 

Results of studies in animals show that effects of 1,3-DNB and 1,3,5-TNB on the blood are similar to the effects seen in people. Results from animal studies also show some other effects of 1,3-DNB exposure, such as behavioral changes, damaged sperm production, and male reproductive damage. We do not know if these other effects could occur in people. Animal studies also show that, in certain cases, a large enough single oral dose of 1,3-DNB can cause death. Neither 1,3-DNB or 1,3,5-TNB have been tested to see whether or not they cause cancer in animals. 

In reproductive smdies, male rats treated at 3.0 mg/kg from day 15 to 21 of gestation had reduced sperm production in adulthood. ... 

Aerosol - Doses administered to mice between 35 and 150 mg/kg/day resulted in significant seminiferous tubule atrophy, decreased sperm concentrations, and increased numbers of sperm with abnormal morphology. Partial recovery of sperm production was apparent 3 to 6 months following dose cessation. Testicular lesions (tubular atrophy) in adult rats at oral dose levels as low as 16 mg/kg/day was shown. 

Myelosuppression is the most common serious adverse effect of ganciclovir treatment therefore, patients blood counts should be closely monitored. Neutropenia and anemia have been reported in 25 to 30% of patients, and thrombocytopenia has been seen in 5 to 10%. Elevated serum creatinine may occur following ganciclovir treatment, and dosage adjustment is required for patients with renal impairment. In animal studies, ganciclovir causes decreased sperm production, teratogenesis, and tumor formation. 

Testis histopathology Mating impairment of hormone production leading to lack of appropriate mating behavior Fertility sperm production/function affected... 

Malepatientsshouldbeawarethat ganciclovir may temporarily or permanently inhibit sperm production... 

These steroids control the development of male characteristics sperm production and growth of the sex organs (penis, testes), prostate, and seminal vesicles (their androgenic... 

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