Effects of prolactin on aldosterone secretion in rat zona glomerulosa cells

Acute effects and action mechanisms of prolactin (PRL) on aldosterone secre tion in zona glomerulosa (ZG) cells were investigated in ovariectomized rat s. Administration of ovine PRL (oPRL) increased aldosterone secretion in a dose-dependent manner. Incubation of [H-3]-pregnenolone combined with oPRL increased the production of [H-3]-aldosterone and [H-3]-deoxycorticosterone but decreased the accumulation of [3H]-corticosterone. Administration of o PRL produced a marked increase of adenosine 3',5'-cyclic monophosphate (cAM P) accumulation in ZG cells. The stimulatory effect of oPRL on aldosterone secretion was attenuated by the administration of angiotensin II (Ang II) a nd high potassium. The Ca2+ chelator, ethylene glycol-bis(beta-aminoethyl e ther)-N,N,N',N'-tetraacetic acid (EGTA, 10(-2) M), inhibited the basal rele ase of aldosterone and completely suppressed the stimulatory effects of oPR L on aldosterone secretion. The stimulatory effects of oPRL on aldosterone secretion were attenuated by the administration of nifedipine (L-type Ca2channel blocker) and tetrandrine (T-type Ca2+ channel blocker). These data suggest that the increase of aldosterone secretion by oPRL is in part due t o (1) the increase of cAMP production, (2) the activation of both L- and T- type Ca2+ channels, and (3) the activation of 21-hydroxylase and aldosteron e synthase in rat ZG cells. J. Cell. Biochem. 72:286-293, 1999. (C) 1999 Wi ley-Liss, Inc.