title: Ex vivo effect of insulin on normal and diabetic rat hearts hypoperfused with norepinephrine.
abstract: The effect of ex vivo insulin on contractile and energy metabolism dysfunctions was examined during hypoperfusion (0.6 ml/min per g heart weight) with 10(-6) M norepinephrine in isolated non-diabetic and streptozotocin-diabetic rats hearts. Insulin (2 mU/min per g heart weight) was infused for 15 min before as well as during 60-min hypoperfusion. Insulin significantly reduced the elevated diastolic tension in diabetic hearts (from 3.8 to 0.7 delta g), but not in non-diabetic hearts (from 1.4 to 1.2 delta g). Insulin partly improved the ATP decrease in the subendocardium of the left ventricle of the diabetic hearts (from 3.5 to 10.2 mumol/g dry weight) but did not affect non-diabetic hearts (from 6.9 to 6.8 mumol/g dry weight). Insulin also partly improved the creatine phosphate decrease and the inorganic phosphate increase in diabetic hearts only. Lactate accumulation was greater in non-diabetic than in diabetic hearts, even in the presence of insulin (77 vs. 45 mumol/g dry weight). The results indicate that acute intracoronary application of insulin in diabetic hearts improves hypoperfusion with norepinephrine injury to a level above that of non-diabetic hearts, but does not improve a less severe injury in non-diabetic hearts.
authors.affiliation: Department of Pharmacology, School of Medicine, University of Ryukyus, Okinawa, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Higuchi
authors.forename: K
authors.initials: K
authors.lastname: Uezu
authors.forename: M
authors.initials: M
authors.lastname: Sakanashi
mesh_terms: D000818:Animals; D002560:Cerebrovascular Circulation / Q000187:drug effects; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D004734:Energy Metabolism / Q000187:drug effects; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology*; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D009638:Norepinephrine / Q000008:administration & dosage*; D010477:Perfusion; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values
chemical_list: D007328:Insulin; D007773:Lactates; D019344:Lactic Acid; D009638:Norepinephrine