The significance of plasma gastrointestinal glucagon in endotoxemia

Hyperglucagonemia has been reported during endotoxemia. Increases in plasma glucagon concentration may serve as an important mediator and be influential in modifying metabolism during endotoxin shock. Increases in the plasma concentration of glucagon are brought about by both pancreatic and gastrointestinal release of glucagon during endotoxemia. The purpose of the present study was to determine the importance of gastrointestinal-derived glucagon (glucagon-like immunoreactivity; GLI) during endotoxin shock. LD100 endotoxin (3.0 mg/kg) was injected via the auricular vein into fasted rabbits. Emphasis was focused on total glucagon and gastrointestinal glucagon (GLI) concentrations, but measurements of these parameters were supplemented by determinations of glucose and triglyceride. The results were as follows: 1) gastrointestinal glucagon concentration increased threefold over that of pancreatic glucagon concentration and 27-fold over that of the control group at 6 hr after endotoxin administration and 2) significant increases of both serum glucose and triglyceride concentrations were observed after endotoxin was injected. Findings suggest that gastrointestinal glucagon may be one of the factors responsible for evoking the abnormal metabolism caused by endotoxin shock. In hyperglucagonemia resulting from endotoxemia, it is suggested that attention should be paid not only to the glucagon originating from the pancreas but also to that derived from the intestine.