Histochemical studies on the developing adrenal gland of Gallus domesticus

Summary The distribution of adrenaline, noradrenaline, aliesterases and non-specific cholinesterases in the cortical and medullary cells and that of ascorbic acid in the cortex have been studied histochemically in sections of adrenal glands from embryonic, juvenile and adult chicken. Both the catecholamines are secreted by the embryonic medulla from the 11th day of incubation but noradrenaline is the more abundant of the two hormones at all stages and it is secreted by the majority of chromaffin cells. There is a tendency for the adrenaline-secreting cells to predominate in the subcapsular layer of the medulla. Both types of chromaffin cells reveal considerable cholinesterase activity consistently from the second half of incubation period onwards.A high concentration of aliesterases and ascorbic acid are developed and maintained in the cortical cords from the time the cortex begins secretory activity, namely, the 10-day incubation stage. Lower concentrations of cholinesterases are also present in the cells of the cortex. The cords of the peripheral zone of cortex show higher concentrations of both the enzymes and ascorbic acid than those of the central zone.From a thesis submitted to McGill University, Montreal, Canada in 1963 in partial fulfillment of the requirements for the degree of Doctor of Philosophy. The work was done during tenure of a Canadian Commonwealth Scholarship.