Inhibitory mechanisms of insulin secretion associated with hypothermic open-heart surgery.

In order to clarify the inhibitory mechanism of insulin secretion associated with open-heart surgery, the influence of insulin antagonistic hormones on insulin secretion was studied in 20 patients with congenital heart diseases undergoing open-heart surgery, under simple deep hypothermia. Despite a hyperglycemia, plasma immunoreactive insulin and C-peptide showed no change during the cooling period, while with the exception of plasma human growth hormone, dopamine-beta-hydroxylase, immunoreactive glucagon, cortisol and cyclic AMP in plasma, either showed no change, or a decrease during the cooling period. It is assumed that catecholamine, glucocorticoid and glucagon do not play an important role in the inhibitory mechanism of insulin secretion during hypothermic open-heart surgery, and a transient hypofunction of the pancreas as well as the liver and the adrenal gland is probably involved.