Neuropeptide-Y acutely stimulates rat zona glomerulosa in vivo

Neuropeptide-Y (NPY) acutely enhanced the plasma concentration of aldosterone (but not that of corticosterone) in both normal animals and in rats whose hypothalamo-hypophyseal axis and renin-angiotensin system were pharmacologically interrupted. The maximal response was obtained with a dose of 150 micrograms/kg. This dose of NPY raised the activity of 11 beta-hydroxylase and 18-hydroxylase in the capsular adrenal (zona glomerulosa), but not that of 11 beta-hydroxylase in the inner adrenocortical layers (zonae fasciculata and reticularis). These findings seem to indicate that NPY is specifically and directly involved in the acute stimulation of the late steps of the secretory activity of the rat zona glomerulosa.