Comparison of the effects of cerebellin and cerebellin analog [Des-Ser(1)]-cerebellin on the secretion of rat adrenal cortex: in vitro and in vivo studies

We compared the effects of cerebellin and its analogue [Des-Ser(1)] -cerebe llin on the secretory activity of rat adrenal cortex. Both peptides (15 nmo les/kg) acutely increased plasma concentrations of aldosterone and corticos terone, without affecting ACTH blood level. Cerebellin (from 10(-12) to 10( -6) M) did not affect basal and ACTH (10(-9) M)-stimulated steroid-hormone secretion from dispersed adrenocortical cells. [Des-Ser(1)] -cerebellin, li ke cerebellin, was ineffective on aldosterone secretion from zona glomerulo sa, but at a concentration of 10(-6) M inhibited either basal or agonist-st imulated corticosterone production by dispersed zona fasciculata-reticulari s cells. Taken together, these findings (i) confirm that cerebellin exerts an ACTH-independent adrenocortical secretagogue effect, acting indirectly o n adrenocortical cells; and (ii) suggest that [Des-Ser(1)] -cerebellin, alt hough largely mimiking cerebellin effects, at muM concentration is able to bind receptors negatively coupled with the steroidogenic pathway of zona fa sciculata-reticularis cells.