EFFECT OF GLUCOCORTICOIDS ON TESTOSTERONE PRODUCTION IN TOAD TESTES

GARCIA, S.B.; DENARI D.; MALAMUD F.; CEBALLOS N.R.

Rosario, Santa Fe, Argentina

Congreso; SAIB; 2006

In mammals, glucocorticoids (GC) inhibit testosterone (T) synthesis through the glucocorticoid receptors (GR). In toad testes, a GR similar to rat receptor was also described. The aim of this work is to analyze the effect of GC on spermiation and steroidogenesis by culturing testes with dexamethasone (DEX),corticosterone (B), with or without RU486 and glycyrrhetinic acid (GA), an 11-hydroxysteroid dehydrogenase type 2 (11HSD-2) inhibitor. After 24-hr incubation, spermiation and T production were assayed. T was measured by RIA while hCG-induced spermiation by counting spermatozoa in the media. GC decreases T secretion, the effect being abolished by RU486. However, the ratio hCG-induced/basal T production was not modified. The effect of low doses of GC was enhanced by GA, suggesting that 11HSD-2 modulates the effect. After 24-hr preincubation, hCG-induced spermiation decreases but in the presence of 15 nM DEX or 15 and 150 nM B spermiation is similar to control. These results suggest that physiological concentrations of CORT revert the negative effect of preincubation on spermiation. The presence of GA does not modify the effect of CORT on hCG-induced spermiation. As with T biosynthesis RU486 completely abolished the effect of CORT suggesting that the action of GC on spermiation and T production is due to its interaction with the type 2 or GC receptor on different cell types.