RESUMO
In this paper, we studied the effect of heme availability on corticosterone and aldosterone synthesis in rat adrenal. We found that hemin stimulated corticosterone and aldosterone production in adrenal homogenates in a dose-dependent fashion. Hemin administration to rats also provoked an increase in both corticosterone and aldosterone content in adrenal. 3,5-Diethoxycarbonyl-1,4-dihydro-2,4,6-trimethylpyridine (DDC), an inhibitor of liver ferrochelatase activity, was able to inhibit this enzyme in rat adrenal. This resulted in an impairment of heme concentration and consequently adrenal ALA-synthase and porphyrin content were increased. Thus, it was proven that DDC inhibits heme biosynthesis in adrenal as it does in liver. In vivo experiments with rats showed that DDC was able to partially blocked ACTH-mediated corticosterone and aldosterone production while hemin administration was able to partially restore it. These data indicate that heme availability affects steroid biosynthesis in rat adrenal.