An Electron Microscopic Correlation of Structure with Function in the Isolated Perfused Cow Adrenal, Preliminary Observations

The isolated adrenal gland of the cow can be used in experiments devised to reveal correlations of cellular function mad structure. Structure may be studied by the electron microscope. Function in the adrenal cortex appears as the synthesis of adreuocorticoid hormones, which can be separated from the effluent perfusion fluid and identified and measured quantitativdy by column and paper chromatogrsphy. The hormones formed are primarily cortisol and corticosterone, with trace amounts of other substances such as aldosterone. Isolated cow adrenals perfused with homologous blood can respond to added ACTH by a manyfold acceleration of corticoid biosynthesis. Intact glands are remarkably sensitive and are maximally stimulated by only 0.1 to 1.0 nv. of ACTH per liter of blood. In contrast, slices of the same gland require more than 38 r.u. of ACTtt per liter for maximal stimulation, and tissue homogenates are totally unresponsive to ACTH, although the homogenates are still able to synthesize corticosteroids (1, 2). Thus, for the cow