Adrenaline formation in noradrenaline-storing chromaffin cells in vitro induced by corticosterone

Organ cultures of extra-adrenal chromaffin cells obtained from 2-day-old rabbits were prepared in a medium composed of horse serum and Medium 199. Corticosterone, 10 μg./ml., was added to half the cultures; the remainder served as controls. After 6 days the explants were examined histochemically by light and electron microscopy or were homogenized and assayed for adrenaline and noradrenaline.

There was a marked increase in the concentration of adrenaline in the corticosterone-treated explants, accompanied by light and electron microscopic histochemical evidence for adrenaline storage. Mixtures of adrenaline- and noradrenaline-storing chromaffin granules were observed in the same chromaffin cell in corticosterone-treated specimens. The control cultures showed little change.

These findings are in keeping with the hypothesis that the local concentration of adrenocortical steroids is an important factor in determining whether chromaffin cells synthesize and store adrenaline or noradrenaline. At a concentration of corticosterone similar to that found in the adrenal venous sinuses of the normal rabbit substantial quantities of adrenaline appear in cells which normally almost entirely store noradrenaline.