Rat liver-pancreas preparation: perfusion technique and metabolic functions
Striffler, J.S.; Curry, D.L.
American Journal of Physiology 237(4): E340-E348
1979
ISSN/ISBN: 0002-9513 PMID: 495712 Document Number: 146843
A technique for in situ perfusion of rat liver-pancreas preparations is described. Dual cannulation of both the aorta and superior mesenteric vein allowed the livers of these preparations to be perfused at rates necessary for maintenance of metabolic viability without subjecting the pancreatic component to excessively high perfusion pressure. Whereas, a variety of studies can be conducted independently on the pancreas or the liver as well as with the 2 combined, the liver-pancreas preparation serves as a unique model for studying hepatic clearance of endogenously released insulin. Glucose-induced biphasic insulin release and glucagon secretion during perfusion with glucose-free perfusate indicated completely normal functioning of the endocrine pancreas during the 90 min period of perfusion of the pancreatic component. Due to the action of endogenously released glucagon, the livers of preparations from fed rats released glucose at maximal rates near 0.80 (mg/min)/g wet liver tissue. Viability of the hepatic component was assessed over an additional 90 min in terms of ratio to 10 to 20 after substrate addition is demonstrated for preparations from fed rats and rats fasted 24 and 48 h. In preparations from 48 h fasted animals, ornithine - (10 mM) and ammonium chloride- (2.7 mM) stimulated ureogenesis of maximum capacity near 2.00 (.mu.mol/min)/g liver is measurable over the 3 h period of perfusion. No proteolytic activity is demonstrable in the hepatic effluent perfusate during perfusion. The functional viability of the liver of the perfused liver-pancreas preparation persists for at least 3 h.