Effects of mGnRH on testicular steroidogenesis in the toad Bufo arenarum

Author： Canosa L.F. Pozzi A.G. Somoza G.M. Ceballos N.R.

ISSN： 0016-6480

Source： General and Comparative Endocrinology, Vol.127, Iss.2, 2002-06, pp. : 174-180

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Abstract

GnRH controls vertebrate reproduction in several ways. This hormone not only affects the secretion of gonadotropins from the pituitary gland but also has a direct influence on several gonadal functions such as steroidogenesis, spermatogenesis, and spermiation. In the present paper we have studied the in vitro effects of GnRH on the testicular steroidogenesis ofBufo arenarum to ascertain the role of this peptide in the control of the steroidogenic pathway previously described in this species. It was found that GnRH is able to reduce basal as well as hCG-stimulated testosterone release, having an inhibitory effect onP450_c17 activity. Thus, GnRH could be involved in the mechanism that regulates the metabolic change in the testicular steroidogenesis. Additionally, testicular GnRH binding site has been characterised, showing aK_d of 34 nM and a maximum binding of 4.7 pmol/mg protein.© 2002 Elsevier Science (USA)