Adrenal steroid secretion and a renal-pressor system in the chicken ( Gallus domesticus)

Abstract

The concentrations of aldosterone and corticosterone in adrenal vein plasma were measured by the double isotope derivative assay in intact cockerels and in cockerels following hypophysectomy, infusion of ACTH, infusion of chicken kidney extracts, or sodium depletion. In sodium-depleted cockerels, renal renin content, index of juxtaglomerular granularity (JGI), and the width of the peripheral zone of the adrenals were also examined. The adrenal vein plasma levels of corticosterone and aldosterone in intact “surgically stressed” cockerels were 6.58 ± 1.47 (SEM) and 0.21 ± 0.06 μg/100 ml, respectively. Infusion of porcine ACTH produced a significant increase in corticosterone but no increase in aldosterone. Concentrations of both steroids were significantly decreased by hypophysectomy while neither sodium depletion nor infusion of chicken kidney extracts produced a detectable change in adrenal veins levels of these steroids. Sodium-depleted cockerels showed a significant increase in JGI. Kidney extracts from sodium-depleted cockerels, when incubated with chicken plasma, produced a significantly greater blood pressure increase in a rat than did kidney extracts from sodium-repleted cockerels. The peripheral zone of adrenals from sodium depleted birds was wider than that of control birds. It is suggested that the pituitary plays a role in maintaining adrenal secretion of aldosterone as well as corticosterone in cockerels. A renal-pressor system was found to be present in the cockerel and could be stimulated by sodium depletion although no steroidogenic action of this system was demonstrable.