Role of the sympatho-adrenal system in the control of endocrine pancreas during haemorrhage in cats

Abstract

Glucose, insulin and glucagon concentrations were determined before, during and after a 60-min period of haemorrhagic hypotension at 60 mm Hg in controls, adrenalectomized and splanchnicectomized cats. Peak increase of arterial plasma glucose concentration in response to haemorrhage was 13.7 +/- 4.3 mM in controls, 10.2 +/- 2.8 mM in adrenalectomized and 3.1 +/- 1.7 mM in splanchnicectomized cats, respectively. Peak portal insulin decrease was 58 +/- 8 and 36 +/- 14 pmol/l in controls and adrenalectomized cats, respectively, whereas insulin levels increased slightly in splanchnicectomized cats during hypovolaemia. Portal plasma glucagon concentration rose by about 250 pmol/l in response to bleeding in all groups of cats. We conclude that the prompt hyperglycaemic and hypoinsulinaemic response to haemorrhage in cats are caused by an adrenergic, 'non-medullary' mechanism, whereas the marked rise in pancreatic glucagon release seems due to factors unrelated to the sympatho-adrenal system.