
%0 Journal Article
%A McFarlane, JR 
%A de, Kretser DM 
%A Risbridger, GP 
%T Stimulatory and inhibitory factors of Leydig cell steroidogenesis are secreted simultaneously by the rat seminiferous tubules and do not affect Leydig cell inhibin production in vitro
%J Reproduction, Fertility and Development
%D 1994/12/01
%V 6
%N 6
%P 693-698
%K 
%R https://doi.org/10.1071/RD9940693
%U https://www.publish.csiro.au/paper/RD9940693 
%X The effect of conditioned medium from rat seminiferous tubules (at Stages VII-VIII and Stages IX-VI) cultured with or without follicle-stimulating hormone (FSH) on the production of testosterone and immunoactive inhibin by Leydig cells was examined. Low doses of conditioned medium from unstimulated tubules at Stages VII-VIII significantly (P < 0.05) increased the mean testosterone production to greater than 31 +/- 11% over that achieved with luteinizing hormone (LH) alone. At the highest dose, the conditioned medium significantly inhibited (P < 0.05) LH-stimulated testosterone production by 13 +/- 7%. Low doses of conditioned medium from unstimulated tubules at Stages IX-VI increased the mean testosterone production to 22 +/- 10%, whereas at higher doses, a significant reversal in the stimulation occurred although not to the same extent as that found with medium from tubules at Stages VII-VIII. Conditioned medium from FSH-stimulated tubules at Stages VII-VIII and Stages IX-VI, significantly increased testosterone production to 39 +/- 7% and 31 +/- 13% respectively. Immunoactive inhibin production by the Leydig cells remained unaffected by exposure to conditioned medium from FSH stimulated and unstimulated tubules at Stages VII-VIII and Stages IX-VI. The data demonstrate that tubule culture medium contains FSH-modulated activities which can specifically stimulate and inhibit testosterone synthesis by adult rat Leydig cells in vitro and therefore explains the contradictory reports in the literature. 
