puberty causes spermatogenesis to begin.
when does spermatogenesis begin what causes it to begin?
puberty
hormonal control of spermatogenesis varies among species. in humans the mechanism is not completely understood; however it is known that initiation of spermatogenesis occurs at puberty due to the interaction of the hypothalamus, pituitary gland and leydig cells. if the pituitary gland is removed, spermatogenesis can still be initiated by follicle stimulating hormone (fsh) and testosterone. in contrast to fsh, lh appears to have little role in spermatogenesis outside of inducing gonadal testosterone production.
spermatogenesis
bicalutamide monotherapy seems to have minimal effect on testicular spermatogenesis, testicular ultrastructure, and certain aspects of male fertility. this seems to be because testosterone levels in the testes (where ≈95% of testosterone in males is produced) are extremely high (up to 200-fold higher than circulating levels) and only a small fraction (less than 10%) of the normal levels of testosterone in the testes are actually necessary to maintain spermatogenesis. as a result, bicalutamide appears to not be able to compete with testosterone in this sole part of the body to an extent sufficient to considerably interfere with androgen signaling and function. however, while bicalutamide does not seem to be able to adversely influence testicular spermatogenesis, it may interfere with -dependent sperm maturation and transport outside of the testes in the epididymides and vas deferens where androgen levels are far lower, and hence may still be able to impair male fertility. in addition, the combination of bicalutamide with other medications, such as estrogens, progestogens, and analogues, can compromise spermatogenesis due to their own adverse effects on male fertility. these medications are able to strongly suppress gonadal androgen production, which can severely impair or abolish testicular spermatogenesis, and estrogens also appear to have direct and potentially long-lasting cytotoxic effects in the testes at sufficiently high concentrations.
bicalutamide