Release of ouabain-like compound (OLC) from the intact perfused rat adrenal gland

Abstract

The present study was designed to investigate the effect of ACTH on release of OLC from the intact isolated rat adrenal, perfused in situ. OLC was measured by EIA. The limit of detection of the assay was 23 pmol/10 minutes. Basal levels of OLC varied from 240 to <23 pmol/10 min. Basal corticosterone levels were generally higher than OLC while aldosterone were generally lower. In 3 of the 5 perfusions the addition of ACTH was followed by rapid increases in both OLC and corticosterone secretion rates within 10 minutes of stimulation. Stimulated levels of OLC were 2 to 4-fold and of corticosterone were 3 to 7-fold those found in basal samples. OLC was found to co-elute with authentic ouabain under isocratic HPLC analysis whilst perfusion medium itself contained no detectable OLC immunoreactivity. These preliminary data suggest that the intact perfused rat adrenal preparation is a useful model for investigating the acute regulation of OLC secretion.