Glucagon test for insulinoma: a chemical study in 25 cases

Abstract

SYNOPSISThe capillary blood glucose response to lmg of intramuscular glucagon was determined in 13 patients with insulinoma and in 33 normal controls; the insulinoma patients showed a normal initial rise, but this was followed by an abnormally large fall, reaching hypoglycaemic levels between 90 and 180 minutes in every case. In 14 insulinoma patients the response of venous blood glucose and also plasma insulin to lmg of intravenous glucagon was compared with 10 normal controls; there was an abnormally large rise of plasma insulin in 10 of the 14 patients, and in the majority the venous blood glucose was below normal throughout the test. In these 14 patients the plasma insulin response was also determined after oral and intravenous glucose, after oral leucine, and after intravenous tolbutamide, and the value of these tests in the recognition and differential diagnosis of insulinoma was compared with that of the intravenous glucagon test. MATERIALS AND METHODSTwenty-five patients with hyperinsulinism were studied, two of them (A.B. and W.K.) on more than one occasion. In 24 patients an insulinoma was found at operation; 18 were benign and five were malignant with metastases. The remaining patient (W.K.), who at first refused operation, was operated upon four years later but no tumour found though clinically the diagnosis was not in doubt; both fasting hypoglycaemia and hyperinsulinaemia persisted postoperatively. In addition two patients with hypoglycaemia due to extrapancreatic neoplasms, four with hepatogenous hypoglycaemia, three with essential reactive hypoglycaemia, and one with hypoglycaemia due to hypopituitarism were also studied.Control subjects were healthy laboratory personnel, or non-obese, non-diabetic hospital inpatients free from endocrine, hepatic, or metabolic disease. In addition five healthy, obese, non-diabetic subjects were investigated.Glucagon tests were carried out on patients and controls maintained on a high carbohydrate diet by one of the following procedures.

Hiperinsulinismo endógeno: revisão e seguimento de 24 casos

“…Portadores de insulinoma podem demonstrar uma resposta excessiva de insulina e subsequente hipoglicemia após injeção endovenosa (EV) de 1 mg de glucagon (34). Em indivíduos normais, a glicose plasmática se eleva, atingindo o pico após 20 minutos, voltando aos níveis basais ao término do teste.…”

“…Em indivíduos normais, a glicose plasmática se eleva, atingindo o pico após 20 minutos, voltando aos níveis basais ao término do teste. A insulina atinge seu pico após 5 minutos do início deste, caindo gradativamente até o tempo de 120' (34). O limite superior do normal (Média + 2DP) para o pico de insulina é de 130 uUmL (34,35 (34,36).…”

“…A insulina atinge seu pico após 5 minutos do início deste, caindo gradativamente até o tempo de 120' (34). O limite superior do normal (Média + 2DP) para o pico de insulina é de 130 uUmL (34,35 (34,36). Entretanto, nosso estudo sugere que a presença de níveis de glicose plasmática no tempo 120' do teste do glucagon inferiores a 50 mg/dL e ao valor basal reforça fortemente a hipótese de insulinoma.…”

Glucose-responsive and Octreotide-sensitive Insulinoma

“…P o s t o p e r a t i v e Or a l a n d I n t r a v e n o u s Gl u c o s e T o le r a n c e T e s t s nomas (12)(13)(14), β-cell tumors have occasionally been shown to hyperrespond to a variety of normal insulin secretagogues, such as glucagon, leucine, tolbutamide, and calcium (12,13,(15)(16)(17)(18)(19) …”

Diagnostic Value of Intravenous Glucagon Test in Insulinoma

“…However, there are a few reports in which the glucagon test is evaluated in comparison with other tests (Marks and Samols 1968;Vance et al 1972). An intravenous glucagon test was carried out after an overnight fast.…”