OCTREOTIDE EXACERBATED FASTING HYPOGLYCEMIA IN A PATIENT WITH A PROINSULINOMA - THE GLUCOSTATIC IMPORTANCE OF PANCREATIC GLUCAGON

Octreotide, a long-acting somatostatin analogue, has been used to alle viate hypoglycaemia In patients with insulinomas. Transient worsening of fasting hypoglycaemia following octreotide has also been described (Stehouwer et al., 1989). We describe a patient with a 'proinsulinoma' in whom octreotide caused rapid and prolonged symptomatic worsening o f fasting hypoglycaemia. Catecholamine and cortisol counterregulatory hormonal responses were normal but those of glucagon and GH were impai red. Acute neuroglycopaenic symptoms were present during octreotide in duced hypoglycaemia, which was accompanied by and attributed to an acu te reduction in pancreatic glucagon secretion in the presence of persi stent and unsuppressed hyperproinsulinaemia. This suggests that glucag on may be important in maintaining glucose homeastasis in chronic hypo glycaemia due to endogenous hyperinsulinism even though its concentrat ion in the peripheral blood is not raised.