Pendrin localizes to the adrenal medulla where it modulates catecholamine release (701.1)

Abstract

Pendrin is an aldosterone‐sensitive, Na+‐independent Cl‐/HCO3‐ exchanger expressed in intercalated cells within the renal cortex where it modulates blood pressure. Since pendrin gene ablation stimulates the release of renin, but not aldosterone, we hypothesized that pendrin is expressed in the adrenal gland and modulates adrenal function. Thus, we examined rat and mouse adrenal pendrin mRNA and protein abundance by PCR, immunoblot and immunohistochemistry and examined adrenal responses in wild type and pendrin null mice. Pendrin protein was detected in adrenal lysates from wild type, but not pendrin null mice. In both mice and rats, we observed pendrin mRNA and protein in the adrenal medulla but not in the adrenal cortex. Since the adrenal medulla produces catecholamines, further experiments examined plasma epinephrine responses to 5 and 20 min of immobilization stress in wild type and pendrin null mice. Basal epinephrine concentration was similar in wild type and pendrin null mice. Immobilization stress increased epinephrine in both groups, but responses were ~50% higher in pendrin null vs wild type after either 5 or 20 min of immobilization stress (20 min: KO, 1562 ± 263, n=4, vs WT, 1041 ± 129 pg/ml, n=6, P < 0.05). We conclude that pendrin is expressed in the adrenal medulla where it may blunt stress‐induced epinephrine release.Grant Funding Source: Supported by NIH