Implication of ZOG protein (zona glomerulosa-specific protein) in zone development of the adrenal cortex

The three zones of adrenal cortex are thought to arise from a single multip otential stem cell. Immunohistochemical studies of fetal and adult adrenals using an antibody against a previously-cloned ZOG protein, a rat homolog o f Pref-1, were conducted to explore its roles in the differentiation of cor tical tissues. At the early embryonic stage, ZOG was already expressed in a drenogonadal primordial cells. The ZOO-positive cells gradually formed the adrenal primordium by E14.5. By E17.5 the expression was repressed in the i nner part of the aggregate and these cells began to express CYP11B1. The ZO O-positive cells at this stage existed at the periphery of the aggregate bu t they did not express CYP11B2 yet. Not until E20.5 did the aldosteronogeni c cells appear among the ZOO-positive cells at the outermost part of the gl and. Based on these and the other findings the zonal development of the adr enal cortex is discussed.