VASODILATION OF RAT RETINAL MICROVESSELS INDUCED BY MONOBUTYRIN - DYSREGULATION IN DIABETES

1-Butyryl-glycerol (monobutyrin) is a simple lipid product of adipocyt es with angiogenic activity. Recent studies have shown that the biosyn thesis of this compound is tightly linked to lipolysis, a process asso ciated with changes in blood flow. We now present data indicating that monobutyrin is an effective vasodilator of rodent blood vessels using a fluorescent retinal angiogram assay. The vasodilatory activity of m onobutyrin is potent (ED50 = 3.3 x 10(-7) M), dose dependent, and ster eospecific. Because diabetes represents a catabolic, lipolytic state w ith numerous vascular complications, we examined the action and regula tion of monobutyrin in insulin-deficient diabetic rats. Serum levels o f monobutyrin in streptozotocin-induced diabetic rats were greatly ele vated compared to normal animals. At the same time, the retinal vessel s of the diabetic animals develop a resistance to the vasodilatory act ivity of monobutyrin. These results demonstrate a role for monobutyrin in the control of vascular tone and suggest a possible involvement in the pathology of diabetes.