Catecholamines storage/secretion

The actions of epinephrine and norepinephrine in the liver, the adipocyte, the skeletal muscle cell, and the a and 3 cells of the pancreas direcdy influence fuel metabolism (Fig. 43.6). These catecholamines are counterregulatory hormones that have metabolic effects directed toward mobilization of fuels from their storage sites for oxidation by cells to meet the increased energy requirements of acute and chronic stress. They simultaneously suppress insulin secretion, which ensures that fuel fluxes will continue in the direction of fuel utilization rather than storage as long as the stressful stimulus persists. 

The molar proportion of catecholamines to adenosine triphosphate in the medulla of the normal human suprarenal gland is about 1 4-5, whereas in tissue from a phaeochromocytoma a proportion of 1 10-35 was found. This observation, coupled with that of decreased granular storage of catecholamines in the cells of a phaeochromocytoma, point to a disturbance in the storage mechanisms of cells from chromaffine tissue tumours. (989,1469) increased secretion from such tumours is probably connected with this disturbance. 

---