Effect of Rat Atrial Natriuretic Factor on in vivo and in vitro Aldosterone and Corticosterone Secretions in the Rat during the Perinatal Period

Abstract

The effect of rat atrial natriuretic factor (rANF) on aldosterone and corticosterone secretion was investigated in vivo in 21-day-old rat fetuses injected intravenously through the umbilical vein and in vitro on isolated adrenal cells from 17-, 19- and 21-day-old fetuses and 1-, 2-, 3- and 4-week-old rats. In vivo, rANF (50 pmol/50 µl/fetus) inhibited both basal levels and secretion of aldosterone stimulated by adrenocorticotropin hormone (ACTH_(1–24), 0.25 pmol/50 µl/fetus), but not corticosterone secretion. In vitro, the addition of graded concentrations of rANF (0.001, 0.01 and 10 nmol/l) to the incubation medium did not affect the basal aldosterone and corticosterone secretions of fetal and neonatal adrenal cells. ACTH_(1–24) (0.1 nmol/l) stimulated productions of both corticosterone and aldosterone by the adrenal cells at all stages studied. The addition of graded concentrations of rANF to the incubation medium containing ACTH_(1-24) (0.1 nmol/l) induced a dose-dependent inhibition of aldosterone secretion by the adrenal cells from 21-day-old fetuses and newborn rats. In contrast, no effect was observed on cells from 17- and 19-day-old fetuses. At all stages investigated, the three doses of rANF were unable to affect ACTH-induced corticosterone secretion in vitro. In isolated adrenal cells from 2-week-old rats, rANF (10 nmol/l) inhibited the secretion of aldosterone induced by ACTH_(1–24) (0.1 nmol/l), and by different steroids of the aldosterone synthetic pathway (progesterone, 11-deoxycorticosterone, corticosterone, 1µ mol/l for each steroid). These results suggest that rANF is a specific inhibitor of aldosterone synthesis in the perinatal period of the rat and that the inhibitory effect of rANF occurs both during the early and late pathways of aldosteroidogenesis.

Effects of dehydration on endocrine regulation of the electrolyte and fluid balance and atrial natriuretic peptide-binding sites in perinatally malnourished adult male rats

“…Recovery of labelled aldosterone from plasma was over 95%. The RIA method for aldosterone has been described previously (51). The specific aldosterone antiserum used had less than 0.001% cross-reactivity with deoxycorticosterone, progesterone and testosterone.…”

Atrial natriuretic peptide and aldosterone secretions, and atrial natriuretic peptide-binding sites in kidneys and adrenal glands of pregnant and fetal rats in late gestation in response to a high-salt diet

“…The plasma aldosterone concentrations were measured by RIA after extraction of aldosterone from the plasma with ethyl acetate after delipidation with iso-octane and assayed as previously described (26). Intra-and interassays were respectively Ϯ 5.00% (n ¼ 11) and 13.00% (n ¼ 7) and recovery of aldosterone from plasma was over 95% (n ¼ 10).…”

Effects of water deprivation on atrial natriuretic peptide secretion and density of binding sites in adrenal glands and kidneys of maternal and fetal rats in late gestation

“…In the control fetal kidney, the weak density of ANPC receptors compared with that of control maternal glomeruli might contribute to the increase in fetal plasma ANP concentrations, which are greater than those of pregnant rats. Indeed, the ANPC receptors are responsible for the degradation of plasma ANP, and, when they are blocked with cANP (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23), the plasma ANP concentrations are much greater (34). In contrast, in the control fetal kidney, the high concentrations of fetal plasma ANP could explain the lower affinity of total ANP receptors.…”

“…Details have been described previously (19). Briefly, aldosterone extracted from plasma samples with ethyl acetate after delipidation with iso-octane was incubated overnight at 4 ЊC with aldosterone antibody (Bioproducts) and 1,2,6,7[ 3 H] aldosterone (Amersham).…”

“…The density of ANPB receptors was assessed with rANP( in the presence of an excess of cANP (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23) (0.1 mmol/l) (Peninsula), a truncated ANP peptide which binds selectively to ANPC receptors. The density of ANPC receptors was obtained by subtracting the number of ANPB receptors from the total receptor population.…”