Role of the symphato-adrenal system in hemorrhagic hyperglycemia

Arterial and venous plasma glucose concentration was determined at intervals in cats subjected to hemorrhagic hypotension at 50 mm Hg. The rapid rise of arterial plasma glucose after hemorrhage could be attributed to an increase release of glucose from the liver. This hyperglycemia could not be eliminated by bilateral adrenalectomy or by sectioning of the hepatic sympathetic nerves, although the response was somewhat depressed by the latter procedure. On the other hand the hyperglycemia was virtully abolished after adrenalectomy when combined with bilateral sectioning of the major and minor splanchnic nerves. The level of plasma glucagon during hemorrgage increased in cats with an intact sympatho-adrenal system, but was unchanged in animals with combined splanchnic sympathectomy and adrenalectomy. It is concluded that, during hemorrhage, the sumpatho-adrenal system influences the glucose output from the liver by three different reflex mechanisms: (a) release of catecholamines from the adrenal glands; (b) direct sympathetic nerve influence on the liver; and (c) release of glucagon from the pancreas.