Antisomatostatin serum increases levels of hormones from the pituitary and gut, but not from the pancreas.

The effects of antisomatostatin serum upon the levels of growth hormone, glucagon-like immunoreactivity (GLI), glucagon, insulin and post-prandial triglyceride levels were examined in a group of 5 dogs before and after a fat-rich meal. Within 1 min after the injection of sheep antisomatostatin, plasma growth hormone and GLI levels increased significantly above baseline levels before the meal and remained elevated for 45 to 60 min after the meal, whereas the administration of nonimmune sheep serum to the same dogs did not cause significant changes in either hormone. Plasma insulin, glucagon and triglyceride levels after antisomatostatin serum were not significantly different from the controls. These findings suggest that endogenous somatostatin influences the secretion of growth hormone and GLI via a pathway readily accessible to intravenously injected antibodies, probably via the circulation, whereas any influence that somatostatin may have upon the secretion of insulin and glucagon must take place via a pathway inaccessible to intravenously administered antisomatostatin serum, i.e. within the islets themselves.