Contractile activity and prostacyclin generation in isolated coronary arteries from diabetic dogs.
The present study was aimed at determining the generation of "prostacyclin (PGI2)-like-material" in coronary arteries from normal and diabetic (pancreatectomized) dogs as well as the contractile responses to prostacyclin of preparations from normal, diabetic and insulin-treated diabetic animals. PGI2 produced a dose-dependent relaxation of coronary arteries from normal dogs. In contrast, those from diabetic animals were not related; indeed, at low concentrations PGI2 failed to evoke any effect but at higher ones it induced a distinct contraction. In arteries from diabetic animals treated with insulin, PGI2 induced a biphasic contractile effect, which lay between that of normal controls and untreated diabetics. In addition the basal generation of "PGI2-like-material" by coronary arteries was significantly higher in the diabetic (141 +/- 0.2 pg/mg, mean +/- SEM) than in normal dogs (59 +/- 0.2 pg/mg). The present experiments demonstrate that the generation of "PGI2-like substance" is significantly increased in coronary arteries from diabetic dogs, but the same vessels are unable to respond to added authentic PGI2 with relaxation; on the contrary they react with a distinct positive contractile response.
D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D011464:Epoprostenol / Q000096:biosynthesis* / Q000494:pharmacology; D066298:In Vitro Techniques; D010180:Pancreatectomy; D011453:Prostaglandins / Q000096:biosynthesis*; D014661:Vasoconstriction / Q000187:drug effects
D011453:Prostaglandins; D011464:Epoprostenol