Regulation of FSH Secretion: Use of Hydroxyurea to Deplete Germinal Epithelium

Abstract

Hydroxyurea, a chemotherapeutic agent that prevents mitosis by inhibiting DNA synthesis, was administered to adult male rats for 70 days. Plasma FSH and LH showed no systematic trend although severe germinal cell depletion was produced. These data suggest that the cell(s) of the seminiferous tubule involved in FSH regulation must be either the type A spermatogonium or the Sertoli cell.

Plasma FSH, LH and testosterone levels in the male rat during degeneration of the germinal epithelium caused by severe heat treatment or ligation of the vasa efferentia

“…However, administration of antispermatogenic chemical agents has been shown to elevate plasma FSH and LH (Debeljuk, Arimura & Schally, 1973) (Gomes, Hall, Jain & Boots, 1973). FSH levels remained unaffected during the period of aspermatogenesis caused by the antimitotic agent hydroxyurea (Mecklenberg, Hetzel, Gulyas & Lipsett, 1975) or by depriving the testis of its specific requirement for vitamin A (Krueger, Hodgen & Sherins, 1974). This lack of uniformity in the changes in circulating gonadotrophin concentrations indicates that the pituitary response is not solely related to the interruption of spermatogenesis.…”

Gonadotrophins, Testosterone and Spermatogenesis in Neonatally Irradiated Male Rats: Evidence for a Role of the Sertoli Cell in Follicle-Stimulating Hormone Feedback

“…Several observations suggest that the Sertoli cells (Christiansen, 1975;Steinberger & Steinberger, 1976) or the Sertoli cells and/or spermatogenic cells (Franchimont, Millet, Vendrely, Letawe, Legros & Netter, 1972;Van Thiel, Sherins, Myers & De Vita, 1972;Krueger, Hodgen & Sherins, 1974;Mecklenburgh, Hetzel, Gulyas & Lipsett, 1975) play a role in the negative feedback action of the testis on peripheral concentrations of FSH.…”

“…Thiel et al (1972),Krueger et al (1974),Christiansen (1975), Mecklenburgh et al (1975 and Steinberger& Steinberger (1976). Other authors have suggested sperma¬ togonia(De Kretser, Burger & Hudson, 1974), spermatocytes(Debeljuk et al 1973;Gomes et al 1973), spermatids(Swerdloff, Walsh, Jacobs & Odell, 1971;Debeljuk et al 1973), residual bodies…”

Pituitary--gonadal axis in sterile male mice heterozygous for autosomal reciprocal translocation T145H

“…A similar conclusion was tentatively drawn from observations on men that had no spermatids and normal FSH plasma levels (Baker et al, 1976); these investigators showed that spermatogonial numbers remained inversely correlated with FSH levels. This has also been confirmed by studies indicating normal FSH secretion in rats with germ cell depletion without reduction in spermatogonial numbers resulting from vitamin A deficiency (Krueger, Hodgen & Sherins, 1974) or hydroxyurea treatment (Mecklenburg, Hetzel, Gulyas & Lipsett, 1975). Reciprocally, the level of FSH was considerably elevated in genetic mutant mice (called Steel) exhibiting morphologically normal Sertoli cells and complete absence of any spermatogenic cells including immature spermatogonia (Younglai & Chui, 1973).…”