The alpha cell response to glucose change during perfusion of anti-insulin serum in pancreas isolated from normal rats.
To determine the effect of neutralization of endogenous insulin upon the glucagon response to a rise and fall of glucose concentration, pancreata isolated from normal rats were perfused with either a potent anti-pork insulin guinea pig serum or a nonimmune guinea pig serum for 30 min. During this period glucose concentration was changed from 100 mg/dl to either 130, 180 or 80 mg/dl for 10 min. Antiserum perfusion at 100 mg/dl caused an approximately two-fold increase in glucagon which was not suppressed by an increase in glucose concentration to either 130 or 180 mg/dl, although glucagon secretion was significantly suppressed in the control experiments in which nonimmune serum was perfused. However, the 0.38 +/- 0.21 ng/min rise in glucagon secretion in response to a reduction in glucose concentration to 80 mg/dl in the control experiments was not abolished by antiserum perfusion but, instead, was enhanced (2.66 +/- 0.60 ng/min). These findings suggest that insulin may be required for glucose-mediated suppression of glucagon in the isolated pancreas of normal rats but not for stimulation of glucagon secretion by mild glucopenia. Alternatively, neutralization of insulin-mediated release-inhibition of glucagon secretion may simply have altered alpha cell responsiveness in a direction that desensitized it nonspecifically to suppression and sensitized it to stimulation.
D000818:Animals; D005934:Glucagon / Q000378:metabolism; D005947:Glucose / Q000008:administration & dosage / Q000494:pharmacology*; D066298:In Vitro Techniques; D007328:Insulin / Q000502:physiology; D007330:Insulin Antibodies / Q000502:physiology*; D007515:Islets of Langerhans / Q000187:drug effects*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains
D007328:Insulin; D007330:Insulin Antibodies; D005934:Glucagon; D005947:Glucose