Norepinephrine-induced 1,2-diacylglycerol accumulation and change in its fatty acid composition in the isolated perfused rat heart.
Phosphoinositide hydrolysis is elicited by alpha-adrenoceptor stimulation in the myocardium, resulting in the generation of 1,2-diacylglycerol by the direct activation of phospholipase C. However, the physiological role of 1,2-diacylglycerol accumulation in the heart has been largely unexplored. Therefore, we studied the effects of norepinephrine on the accumulation of 1,2-diacylglycerol and its fatty acid composition, as well as its function in isolated perfused rat hearts. A 30 min perfusion with norepinephrine following a stabilization period of 25 min caused increases of 68% and 57% in 1,2-diacylglycerol levels in the heart at 10(-6) M and 5 x 10(-6) M, respectively, compared to controls. Analysis of its fatty acid composition showed a significant elevation in the percentages of 18:2 and 20:4 although the absolute amounts of these increases in fatty acids were relatively low when compared to the elevation in the total amount of 1,2-diacylglycerol. The change in contractility was not consistently related to an increase in 1,2-diacylglycerol. These results indicate that the increase in 1,2-diacylglycerol level in response to norepinephrine perfusion was accompanied by a change in fatty acid composition of 1,2-diacylglycerol.
Okumura
K
K
Second Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Shirai
Y
Y
Kondo
J
J
Hashimoto
H
H
Ito
T
T
Ogawa
K
K
D000818:Animals; D004075:Diglycerides / Q000378:metabolism*; D005227:Fatty Acids / Q000032:analysis*; D005989:Glycerides / Q000378:metabolism*; D006321:Heart / Q000187:drug effects*; D008297:Male; D009200:Myocardial Contraction; D009206:Myocardium / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology*; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains
C011439:1,2-diacylglycerol; D004075:Diglycerides; D005227:Fatty Acids; D005989:Glycerides; D009638:Norepinephrine