1994 Volume 64 Issue 2 Pages 65-70
The mechanisms responsible for diabetes mellitus-induced enhancement of prostaglandin (PG) F2α response were investigated in vascular smooth muscles isolated from diabetic mice and rats. Streptozocin (150 mg/kg, i.v. bolus, 6 week-elapsed)-ddY mice and (60 mg/kg, i.v. bolus)-Wistar rats and genetically diabetic GK-rats were used. The responses to PGF2α were enhanced in small blood vessels such as mesenteric arteries (diabetic rats) and veins (diabetic mice) and they were reduced in large blood vessels such as the aorta and vena cava (diabetic rats). The enhanced response to PGF2α in diabetic blood vessels was significantly inhibited by nordihydroguaiaretic acid (NDGA) (0.03 mM) and phenidone (0.05 mM), lipoxygenase inhibitors, cycloheximide (1 mg/kg, i.v.), a protein synthesis inhibitor and actinomycin D (2.8 mg/kg, i.v.), a RNA polymerase inhibitor, but neither inhibited by cyclooxygenase inhibitors, a thromboxane antagonist, nor Ca2+ antagonists. The PGF2α response was also enhanced with aging alone, whereas the extent of enhancement was less than that with diabetes mellitus, and not significantly blocked by NDGA. These results demonstrate that diabetes mellitus-induced imbalance in the regulation of the eicosanoid metabolic pathways (suppressed cyclooxygenase and accelerated lipoxygenase) may cause the enhancement of PGF2α-induced responses in small blood vessels.
