The effects of follicle stimulating hormone and luteinizing hormone on steroid metabolism by isolated seminiferous tubules and interstitial tissue from hypophysectomized and oestrogen-treated rats

Sivelle, P. C.

doi:10.1016/0006-2952(79)90097-2

Cited by 3 publications

(3 citation statements)

References 22 publications

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“…Formation by Sertoli cells of DHT and 3a,17P-diol from androstenedione and testosterone secreted by the Leydig cells may initiate the onset of meiosis in the pubertal rat testis. Surprisingly, Sivelle [65] found that treatment of hypophysectomized adult rats with ovine FSH or LH stimulated the ability of isolated testicular interstitial tissue or seminiferous tubules to convert progesterone to testosterone in vitro.…”

Section: Formation Of Androgensmentioning

confidence: 99%

Role of FSH in the Control of Testicular Function

1981

Archives of Andrology

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Follicle stimulating hormone (FSH) binds to the plasma membranes of Sertoli cells and, apparently, spermatogonia; the hormone may then be taken into the cytoplasm of its target cells and metabolized there. In the immature testis, binding of FSH to Sertoli cells leads to activation of adenylate cyclase, formation of cyclic AMP (CAMP), and activation of a CAMP-dependent protein kinase. There is a subsequent increase in the rates of RNA, protein, and DNA synthesis. Normal adult testis is unresponsive to FSH, one reason being the destruction of CAMP by a phosphodiesterase. After hypophysectomy of adult animals this enzyme disappears and FSH is again able to stimulate RNA and protein synthesis. Other factors contributing to the insensitivity of the mature testis are an FSH binding inhibitor, a protein kinase inhibitor, and inactivation of FSH.FSH increases the formation by Sertoli cells of structural proteins and an androgen-binding protein (ABP) that the Sertoli cells secrete into the extracellular fluid surrounding the cells of the germinal epithelium. It is thought that ABP buffers fluctuations in the concentration of androgen in the extracellular fluid of the germinal epithelium as well as transporting androgen to the lumen of the epididymis.In immature animals FSH increases the number of Sertoli cells, which accounts for the testicular hypertrophy that follows hemicastration. FSH is responsible for maturational changes in immature Sertoli cells and for morphological changes associated with in vitro aggregation of Sertoli cells to form colonies. FSH-induced changes in the shape of Sertoli cells are mediated by a calcium-dependent regulator protein, calmodulin. FSH also stimulates the Sertoli cells to secrete a plasminogen activator whose role is not known.FSH has effects on testicular germ cells in immature animals and during the restoration of spermatogenesis in adults, but it is not known whether the Sertoli cells mediate its actions on the germ cells, though this would seem likely. Administration of FSH to immature rats and mice increases the number of spermatogonia by reducing the proportion that degenerate. This may be due to a stimulatory effect of the hormone on DNA synthesis. Androgen and FSH appear to act synergistically to stimulate accumulation of primary spermatocytes and formation of spermatids in immature rats. During the restoration of spermatogenesis in adult rats and mice FSH also acts synergistically with androgen, increasing the proportions of cells passing through meiosis and spermiogenesis. Immunization experiments suggest that FSH is needed for the formation of normal numbers of spermatocytes and spermatids in immature animals, but studies in adults have given conflicting results.FSH appears to influence development of the interstitial tissue, particularly by inducing luteinizing hormone (LH) receptors on Leydig cells. The presence of some LH may be necessary for FSH to have this effect. FSH can stimulate a number of steroid transformations, such as conversion of testosterone to dihydrotesto...

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Section: Formation Of Androgensmentioning

confidence: 99%

Role of FSH in the Control of Testicular Function

1981

Archives of Andrology

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“…Hence oestrogens inhibit testicular androgen secretion directly at the Leydig cell, as well indirectly at the pituitary level. As to the effect at the testicular level, Rodriguez Rigau et al (1977) reported almost complete suppression of 17a-hydroxylase and increased 2Oahydroxysteroidoxidoreductase activity, whereas Sivelle ( 1979) reported an inhibition of the gonadotrophin stimulated conversion of progesterone to testosterone in vitro. Saez et al (1978) in oestrogen-treated rats observed a decrease of plasma testosterone and of the in vivo steroidogenic response to HCG, before gonadotro.…”

Section: Oestrogens and Anti-oestrogemmentioning

confidence: 99%

“…The effects of ethanol on testicular steroidogenesis have been extensively studied by Van Thiel et al (1975, 1979, but also by Wright (1978), Lindholm et al (1978) and many others.…”

Section: Narcotics -Hallucinogensmentioning

confidence: 99%