Effects of prostaglandins E2, I2 and F2 alpha on the tone of isolated coronary arteries from alloxan-diabetic dogs.

Contractile responses to PGF2 alpha of isolated coronary arteries from 7 healthy and 12 alloxan-diabetic dogs without ketosis were considerably increased by indomethacin and decreased by PGI2. The increasing effect of indomethacin was more prominent on diabetic vessels than on those of normal animals while PGI2 had the same relaxant potency in both groups. The contractions induced by PGF2 alpha were inhibited more effectively by PGI2 than those evoked by PGE2 both in healthy and alloxan-diabetic groups.