Influence of insulin on urinary eicosanoid excretion in rats with experimental diabetes mellitus.

Urinary prostaglandin (PG) and thromboxane (Tx) excretion, measured by radioimmunoassay, were examined in two groups of male Wistar rats made diabetic with streptozotocin, 70 mg/kg, one of which received daily insulin beginning on the 7th day after administration of streptozotocin. In addition, urinary kallikrein excretion and blood pressure were monitored. After the induction of diabetes the profile of urinary eicosanoid excretion was altered. 6-keto-PGF1 alpha and TxB2 excretion increased markedly within 24 to 48 hr and remained elevated for the duration of the study, up to 58 days. PGF2 alpha excretion also increased, the change being apparent after 6 days whereas PGE2 excretion was reduced at this time. Urinary kallikrein excretion was unchanged but blood pressure became elevated above control levels 2 weeks after the induction of diabetes. Insulin treatment, to maintain mean blood glucose levels below 200 mg/dl, resulted in decreased excretion of TxB2, PGF2 alpha and 6-keto-PGF1 alpha. However, excretion of PGE2 and kallikrein were increased after insulin treatment which also prevented the elevation in blood pressure. These studies indicate that insulin treatment of experimental diabetes corrects alterations in renal arachidonic acid metabolism and prevents the associated increase in blood pressure.