Prolonged exercise causes an increase in endothelin-1 production in the heart in rats.
Cardiac myocytes produce endothelin-1 (ET-1). ET-1 has potent positive inotropic and chronotropic effects. We investigated whether production of ET-1 in the heart is altered by prolonged exercise in rats. Rats ran on a treadmill for 45 min. Immediately after this exercise the heart and lungs were quickly removed. Control rats remained at rest during this 45-min period. Expression of preproET-1 mRNA in the heart was markedly higher in the exercised than in the control rats. The peptide level of ET-1 in the heart was also markedly higher in the exercised rats. Expression of endothelin type A- and type B-receptor mRNA and endothelin-converting enzyme mRNA in the heart did not differ between the groups. The peptide level of ET-1 and the preproET-1 mRNA level in the lungs of the exercised rats did not differ from those in the control rats. The present results show that production of ET-1 is markedly increased tissue specifically in the heart by exercise without appreciable changes in endothelin-converting enzyme and endothelin receptor expression. The present study suggests that myocardial ET-1 may participate in modulation of cardiac function during exercise.
Maeda
S
S
Department of Sports Medicine, Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-0006, Japan.
Miyauchi
T
T
Sakai
S
S
Kobayashi
T
T
Iemitsu
M
M
Goto
K
K
Sugishita
Y
Y
Matsuda
M
M
D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000235:genetics; D018076:DNA, Complementary / Q000378:metabolism; D019332:Endothelin-1 / Q000096:biosynthesis* / Q000097:blood; D000072396:Endothelin-Converting Enzymes; D016232:Endothelins / Q000235:genetics; D004837:Epinephrine / Q000097:blood; D008297:Male; D008666:Metalloendopeptidases; D009043:Motor Activity / Q000502:physiology*; D009206:Myocardium / Q000378:metabolism*; D009638:Norepinephrine / Q000097:blood; D011498:Protein Precursors / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017466:Receptors, Endothelin / Q000235:genetics; D012016:Reference Values; D013997:Time Factors
D018076:DNA, Complementary; D019332:Endothelin-1; D016232:Endothelins; D011498:Protein Precursors; D012333:RNA, Messenger; D017466:Receptors, Endothelin; D016282:Aspartic Acid Endopeptidases; D008666:Metalloendopeptidases; D000072396:Endothelin-Converting Enzymes; D009638:Norepinephrine; D004837:Epinephrine