Factors influencing the ‘resting’ secretion of the adrenal medulla

Abstract

As control observations for the subsequent papers of this series, dogs were subjected to the environmental and experimental conditions to be used in the hemorrhage experiments. These conditions included immobilization, anesthesia, discomfort, tissue trauma and repeated observations of ‘resting secretion.’ The adrenal vein was cannulated so that adrenal vein blood could be collected for analysis in both chronic and acute preparations. Determination of catechol amines in adrenal venous blood and in peripheral venous blood were carried out by the method of Weil, Malherbe and Bone. Total adrenal hormone efflux was calculated as the product of concentration and flow. The results indicate that immobilization alone had little effect on adrenal vein catechol amine output. When immobilization was complicated by excitement and struggling, or when there was pain or discomfort involved, the outputs were increased. Barbiturate anesthesia lowered catechol amine secretion and adrenal vein blood flow very markedly. Tissue trauma, including fracture of the long bones, increased secretion of the catechol amines. It is emphasized that all of these ‘control’ factors must be evaluated in experiments involving measurement of catechol amines in the adrenal venous blood.