Increased vasodilatory prostaglandin production in the diabetic rat retinal vasculature.
OBJECTIVE
This study was undertaken in order to investigate whether the production of vasodilatory prostaglandins is increased in the retinal vasculature of the diabetic rat.


METHODS
Diabetes was induced in male Sprague-Dawley rats using streptozotocin. Diabetic rats were left uncontrolled for 3-4 weeks or were treated with insulin replacement throughout the period of diabetes. Control rats were age-matched. Retinal vessels extracted from retinae removed at sacrifice were incubated in a physiological salts solution. Prostaglandin E and prostaglandin I2 were measured in collected medium.


RESULTS
The production of both prostaglandin E and prostaglandin I2 by blood vessels isolated from the retina was increased by approximately 40% in streptozotocin-diabetic rats, compared to controls, within 4 weeks of the onset of diabetes. This increase was reversed by treatment of streptozotocin-diabetic rats with insulin. The increase in prostaglandin production was not due to alteration in the maximal capacity of cyclooxygenase enzyme.


CONCLUSIONS
Increased production of vasodilatory prostaglandins occurs in the rat retinal vasculature early in diabetes. Prostaglandins may contribute to altered retinal hemodynamics in early diabetic retinopathy.
Johnson
E I
EI
Department of Medicine, University of Melbourne, Royal Melbourne Hospital, Parkville, VIC, Australia. e.johnson@medicine.unimelb.edu.au
Dunlop
M E
ME
Larkins
R G
RG
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy / Q000378:metabolism*; D003930:Diabetic Retinopathy / Q000188:drug therapy / Q000378:metabolism*; D011464:Epoprostenol / Q000096:biosynthesis*; D007328:Insulin / Q000627:therapeutic use; D008297:Male; D011458:Prostaglandins E / Q000096:biosynthesis*; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D012171:Retinal Vessels / Q000187:drug effects / Q000378:metabolism*
D001786:Blood Glucose; D007328:Insulin; D011458:Prostaglandins E; D011464:Epoprostenol