Males spermatogenesis

Anway MD, Leathers C, Uzumcu M, Skinner MK. Transgenerational effect of the endocrine disruptor vinclozolin on male spermatogenesis. J Androl 2006 27(6) 868 79. 

Both LH and FSH are referred to as gonadotropins, beoause they aot on the male and female gonads, which results in the production of the sex steroids testosterone and estradiol, respectively. In the female, FSH and LH act in concert in regulating ovarian function egg maturation, ovulation, and transformation of the ruptured follicle into the corpus luteum. In males, spermatogenesis is dependent on these two hormones. Specifically, FSH in females facilitates the maturation of ovarian folliole oells and their secretion of estradiol, whereas in males, it stimulates the maturation of sperm in the testes. In females, LH promotes ovulation, formation of the oorpus luteum, and progesterone secretion in males, it enables the secretion of testosterone from the testes. 

In addition to their endocrine disrupting properties, it must be appreciated that many of the chemicals in question possess more general toxic properties, which may be potentiated by metabolism by the organism. Several PAHs, PCBs and PCDDs are carcinogenic, while certain phthalate esters can enhance the excretion of zinc, potentially leading to zinc deficiency. Zinc, an essential element, plays a vital role in spermatogenesis and mature T-cell production. Deficiency may result in abnormalities of the male reproductive system, depletion of spermatogenesis and suppression of the immune system. 

In summary, although the available reproductive studies indicate endosulfan has no adverse effects on reproductive performance in animals, adverse effects on male reproductive organs have been seen in young rats and mice. The lack of effects seen in the studies that examined reproductive performance (specifically fertility rate) in treated males and females seems difficult to explain, given the finding of altered spermatogenesis in the more recent studies. 

In male rats 2,3,7,8-tetrachlorodibenzo-p-dioxin induced hyperplastic changes and sperm granulomas in the epididymis, but no apparent lethal mutations were noted during post-meiotic phases of spermatogenesis. 

ATANASSOVA N, MCKINNELL C, TURNER K J, WALKER M, FISHER J S, MORLEY M, MILLAR M R, GROOME N p, SHARPE R M (2000) Comparative effects of neonatal exposure of male rats to potent and weak (environmental) estrogens on spermatogenesis at puberty and the relationship to adult testis size and fertility evidence for stimulatory effects of low estrogen lew eh,. Endocrinology. 141 3898-907. 

Winer, M. A., and Wolgemuth, D. J. (1993). Patterns of expression and potential functions of proto-oncogenes during mammalian spermatogenesis. In The Molecular Biology of the Male Reproductive System (De Kretser, D. M., ed.), pp. 143-179. Academic Press, San Diego. 

FSH Pituitary Stimulates follicular growth (female) Enhanced spermatogenesis (male)... 

The major FSH target in the male is the Sertoli cells, found in the walls of the seminiferous tubules of the testis. They function to anchor and nourish the spermatids, which subsequently are transformed into spermatozoa during the process of spermatogenesis. Sertoli cells also produce inhibin (discussed later), which functions as a negative feedback regulator of FSH. The major physiological effect of FSH in the male is thus sperm cell production. 

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... 

New guidelines for fertility assessment (traditional Segment I) studies that have shortened the premating dosing schedule (for example, in male rats from 10 weeks to 4 weeks). There has been an increased interest in assessment of spermatogenesis and sperm function. 

No studies were located regarding developmental effects in humans after inhalation exposure to mirex or chlordecone. Although impaired spermatogenesis among male workers exposed to... 

The gonadotrophic hormones of the pituitary include the interstitial cell stimulating hormone (ICSH), which is present and effective in both males and females, and the follicle stimulating hormone (FSH), which stimulates the development of multiple follicles in females and apparently in males induces spermatogenesis. 

Occupational exposure to 1,2-dibromoethane has been reported to produce adverse effects both on spermatogenesis (sperm concentration) and seminal fluid production (semen volume) in human males (Ratcliffe et al. 1987 Takahashi et al. 1981, Ter Haar 1980). 

The direct effect of inhalation exposure to 1,2-dibromoethane on spermatogenesis in animals has not been studied. Nonetheless, the available data from animal studies indicate that the male reproductive system in rats is affected by exposure to 1,2-dibromoethane at high doses. In all studies discussed below, however, rats had high mortality associated with chemical toxicity and/or chemically-induced neoplasia. It is therefore difficult to attribute effects on the reproductive organs to... 

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