Atrial natriuretic peptide stimulates aldosterone production by turkey (Meleagris gallopavo) adrenal steroidogenic cells.

The inhibitory action of atrial natriuretic peptides (ANPs) on mammalian aldosterone synthesis is well documented. In addition, other work indicates that ANP and an analogue of its second messenger, 8-Br-cGMP, inhibit aldosterone production by chicken adrenal steroidogenic cells. However, the interaction between angiotensin II (AII) and ANP in the regulation of avian aldosterone production is poorly understood because chicken adrenal steroidogenic cells, the commonly used in vitro avian model, are comparatively unresponsive to AII. By contrast, turkey (Meleagris gallopavo) adrenal steroidogenic cells are sensitive to AII. Thus, in the present study, the action of ANPs and related peptides and their interaction with other stimulators of aldosterone production were investigated using freshly isolated and briefly cultured turkey adrenal steroidogenic cells. Surprisingly, several ANPs [rat (r), human (h), chicken (c)], and rat brain natriuretic peptide (rBNP) were as efficacious as [Ile5]AII for stimulating aldosterone production (2 hr) in freshly isolated cell suspensions but were less potent than [Ile5]AII (ED50 of ANPs approximately 5-10 nM; [Ile5]AII ED50 approximately 0.1 nM). In addition, chicken ANP enhanced maximal aldosterone production induced by [Ile5]AII (1 nM), K+ (25 mM), and hACTH-(1-39) (ACTH) (1 nM): maximal enhancement of the action of these secretagogues was +49%, +137% and +15%, respectively (P < 0.05; n = 3). Furthermore, other ANPs and related peptides [rBNP and bovine aldosterone secretion inhibiting factor (bASIF)] enhanced maximal [Ile5]AII-induced aldosterone production: the order of maximal enhancement was rBNP (+180%) > hANP/rANP (+50%) > bASIF (+25%) (P < 0.05; n = 3).(ABSTRACT TRUNCATED AT 250 WORDS)