Timing and Sites of Testicular Effects of FSH in Vivo

Davies, Alun; Lawrence, N. R.

doi:10.1007/978-1-4684-3414-9_20

Cited by 3 publications

(3 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The effect of FSH on germ cell degeneration may be explained by the finding that FSH increases the rate of synthesis of DNA in spermatogonia and preleptotene primary spermatocytes in hypophysectomized prepubertal rats [SS]. FSH also stimulates protein synthesis in germ cells, as well as in Sertoli cells, in hypophysectomized adult mice [18]. Addition of FSH to medium bathing fragments of testes from 21-day-old rats increased the number of spermatocytes present after two weeks; testosterone had a similar effect and the best result was obtained when the medium contained both hormones [36].…”

Section: Nucleic Acid Synthesismentioning

confidence: 99%

Role of FSH in the Control of Testicular Function

1981

Archives of Andrology

Self Cite

View full text Add to dashboard Cite

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...

show abstract

Section: Nucleic Acid Synthesismentioning

confidence: 99%

Role of FSH in the Control of Testicular Function

1981

Archives of Andrology

Self Cite

View full text Add to dashboard Cite

show abstract

“…The stimulatory effect of FSH on testicular protein synthesis in intact immature and hypophysectomized adult rodents is well documented (Means 1975;Davies & Lawrence 1978 before testicular tissue was removed had no effect on the uptake of AIB in vitro (Means 1975). Presumably this negative result was because there is a latency in the effect of FSH on amino acid uptake.…”

Section: Discussionmentioning

confidence: 89%

“…From the dose response graph it was evident that stimulation of AIB transport occurred only if the dose of FSH was moderately large. Doses of similar size are needed for stimulation of RNA or protein synthesis in immature mice (Davies & Lawrence 1978). One reason why a dose of 5 IU was needed may have been that as intact mice were used a low concentration of endogenous FSH was already present in the circulation and this would have caused some stimulation of amino acid trans¬ port even in the control animals.…”

Section: Discussionmentioning

confidence: 97%

Stimulation of transport of alpha-aminoisobutyric acid into the testes of immature mice in vivo by follicle-stimulating hormone

Oza¹,

Meanock²,

Davies³

1982

Acta Endocrinologica

Self Cite

View full text Add to dashboard Cite

Groups of immature mice were injected sc with radiocarbon-labelled alpha-aminoisobutyric acid (AIB) after being given a single sc injection of hFSH or of 0.9% saline. As an index of the transport of AIB, the specific activity of isotope was measured in homogenates of testis and of liver. FSH treatment caused statistically significant increases in the specific activity of isotope in the testes and in the ratio of testicular to liver specific activity. The effect was greatest in 9-day-old mice injected with FSH 16 h before removal of the testes. Uptake of labelled AIB was not stimulated after administration of hCG or testosterone. Doses of cycloheximide sufficient to reduce the rate of protein synthesis by over 99% did not impair testicular uptake of labelled AIB or the influence of FSH on AIB uptake. These results suggest that FSH stimulates amino acid transport into cells of the immature testis and that this action is independent of the stimulatory effect of FSH on testicular protein synthesis.Follicle-stimulating hormone (FSH) has been found to increase the rates of synthesis of ribonucleic acids and of proteins in the testes of intact immature and hypophysectomised adult rats and mice (Means et al. 1980;Davies 1980). Though the effect of FSH on proteins appears to be a result of that on RNA, FSH could additionally facilitate protein synthesis by enhancing transport of amino acids into testicular cells. Two groups of workers have studied this possibility by administering FSH to rats and then measuring testicular uptake of radioactivity-labelled alpha-aminoisobutyric acid (AIB) -a non-physological compound which is transported into cells in a similar manner to physio¬ logical amino acids but which is not incorporated into proteins. Means & Hall (1967) detected no increase in in vitro uptake of AIB in teased testicu¬ lar tissue from immature rats which had been treated with FSH. On the other hand Irusta & Wassermann (1972) reported that in vitro trans¬ port of AIB into testicular tissue was stimulated when intact immature or hypophysectomized adult rats had been treated with FSH in vivo. In the experiments reported in this paper we have reinvestigated this problem, administering both FSH and radioactivity-labelled AIB to intact immature mice in vivo. This protocol was chosen because it was thought to reflect normal physiology more closely than does the uptake of AIB into testicular tissue in vitro. Materials and Methods AnimalsMice of the CFW strain (stock originally supplied by the Laboratory Animals Centre, Carshalton) were main¬ tained under constant conditions of temperature (20°C) and lighting (8 h light: 16 h dark). Groups of 10 to 15new-born male pups were fostered to pairs of lactating mothers. In each experiment foster litter mates were used to form randomized blocks for treatment. Except where specified, mice were sacrificed at 9 days of age. HormonesHuman pituitary follicle-stimulating hormone was ex¬ tracted and assayed as described by Butt 8c Lynch (1974). In an experiment in which the effects of ch...

show abstract

Effects of mammalian gonadotropins (oFSH and oLH) on testicular development in the immature water snake, Nerodia sipedon

Krohmer

1986

General and Comparative Endocrinology

View full text Add to dashboard Cite

Timing and Sites of Testicular Effects of FSH in Vivo

Cited by 3 publications

References 36 publications

Role of FSH in the Control of Testicular Function

Role of FSH in the Control of Testicular Function

Stimulation of transport of alpha-aminoisobutyric acid into the testes of immature mice in vivo by follicle-stimulating hormone

Effects of mammalian gonadotropins (oFSH and oLH) on testicular development in the immature water snake, Nerodia sipedon

Contact Info

Product

Resources

About