Glucagon effect on myocardial transport and utilization of energy-metabolites from the coronary microcirculation in the perfused rabbit heart.
Effect of glucagon on energy-metabolite transport into cardiac muscle was studied during a single transit through the isolated rabbit heart using a rapid paired-tracer dilution method. Kinetic experiments revealed that 1.5 microM glucagon stimulated the influx of palmitate bound to 30 g/litre albumin, by increasing the V 2.3 times and increasing the Km for transport 2.4 times. Tracer uptake of D-glucose, as the only exogenous substrate provided, was increased by 80% by 1.5 microM glucagon. Myocardial utilization of [3H]-or [14C]-labelled short-chain monocarboxylic acids (L-lactate, pyruvate and acetate) was significantly reduced by glucagon, to the same degree as their unidirectional sarcolemmal transport. Inhibition of L-[14C]lactate uptake was dose-dependent and in positive correlation with myocardial lactate production. It is concluded that glucagon may regulate sarcolemmal permeability and myocardial utilization for energy-metabolites from the coronary circulation.
Zloković
B V
BV
Department of Medical Physiology, Faculty of Medicine, Belgrade, Yugoslavia.
Andjelković
I Z
IZ
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D003326:Coronary Circulation; D004734:Energy Metabolism / Q000187:drug effects*; D005260:Female; D005934:Glucagon / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008833:Microcirculation; D009206:Myocardium / Q000378:metabolism*; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000493:pharmacokinetics; D010477:Perfusion; D011817:Rabbits
D010169:Palmitic Acids; D019308:Palmitic Acid; D005934:Glucagon; D005947:Glucose