16ALPHA,18-DIHYDROXYDEOXYCORTICOSTERONE AND BINDING OF ALDOSTERONE TO MINERALOCORTICOID RECEPTORS IN KIDNEY OF ADRENALECTOMIZED RATS

Abstract

It has been recently suggested that 16α,18-dihydroxydeoxycorticosterone (16α,18-diOHDOC) may act as a "positive allosteric effector" of the binding of aldosterone to mineralocorticoid receptors. To test this hypothesis, a series of in vitro and in vivo studies examining the effect of 16α,18-diOHDOC on tritiated aldosterone (3HA) binding to mineralocorticoid receptors was performed. Using kidney slices from adrenalectomized rats, in vitro incubations were made for 20′ at 37C, over a range of concentrations of 3HA plus tenfold dexamethasone to confine tracer binding to mineralocorticoid receptors. At no concentration of 3HA did 16α,18-diOHDOC enhance binding; at all tracer concentrations a sli..