Stimulation of rat adrenocortical cells by glycyrrhizin with special reference to its inhibitory effect on dexamethasone-induced atrophy of the adrenal cortex.

Abstract

Adrenocortical stimulation by glycyrrhizin in male rats of Wistar-strain was confirmed by histometrical and enzyme-histochemical methods, and the effect was compared with that of ACTH. Severe cortical atrophy was induced by dexamethasone administration in a dose of 5mg/kg body weight once daily for 2 weeks. The inhibitory effect of simultaneous administration of glycyrrhizin on the dexamethasone-induced atrophy was less evident than that of ACTH so far as adrenal weight and histometrical observations were concerned. Cortical cell atrophy detectable in animals with 0.25mg/kg of dexamethasone once daily for 2 weeks was considerably inhibited by simultaneous ACTH administra-tion, and the histochemical activity of glucose-6-phosphate dehydrogenase was reduced. The inhibition was less conspicuous with glycyrrhizin. The histochemical activity of alkaline phosphatase and adenosine triphosphatase in the capillary wall in the fascicular and reticular zones was markedly accelerated with glycyr-rhizin and very slightly with ACTH. These histochemical findings essentially conformed to the pattern in the normal animals which were treated with glycyrrhizin or ACTH. It was suggested that the stimulant effect of glycyrrhizin on the adrenocortical cell which resulted in an inhibition of the dexamethasone-induced atrophy is induced through the cortical capillary wall including the adrenal reticuloendothelial cell.