Retinoic acid-induced testosterone production and retinoylation reaction are concomitant and exhibit a positive correlation in Leydig (TM-3) cells

Retinoic acid (RA) exerts diverse biologicaleffects in the control of cell growth in embryogenesis andoncogenesis. The effects of RA are thought to be mediatedby the nuclear retinoid receptors; however, not all theeffects of RA can be explained by the nuclear receptorpathways. Indeed, retinoylation is another mechanism ofaction elicited by RA. In growing TM-3 Leydig cell cultures,the extent of retinoylation depends in a saturable manner onthe initial concentration of 3H-RA, time and cell number. Inaddition, dose-response curves for RA-induced testosteroneproduction and retinoylation are concomitant and exhibit apositive correlation. In the present study we demonstratethat RA is able to influence a retinoylation reaction onprotein(s) probably involved on steroidogenesis.