Intraperitoneal insulin--a dose response curve

To determine a dose response curve for intraperitoneal (i.p.) insulin using Sprague-Dawley rats, human insulin was administered i.p. in 1.5% glucose dialysate at the following doses: 10 U (2.19 U/100 g body wt); 5U (1.23 U/100 g body wt); 2 U (0.49 U/100 g body wt); 1 U (0.27 U/100 g body wt). A bolus injection of glucose was given to elevate blood sugar, followed by infusion of D20%. Blood sugar was maintained at 250 mg/dl by checking at 10 minute intervals and adjusting the IV infusion. Dialysate with regular insulin was instilled after blood sugar was constant for 20 minutes. The end-point was the amount of glucose to maintain a blood sugar of 250 mg/dl after instillation of dialysate and regular insulin. Mean blood sugars were similar within and between each dose group. The effect of regular insulin was noted within 10 minutes. The amount of glucose used with the IV dose differed from all other (p less than 0.05). The amount used by the 5 and 10 U doses of i.p. insulin were similar. Increasing amounts of glucose are required to maintain the blood sugar at increasing doses of intraperitoneal regular insulin up to 5 U. Thus, there appears to be a dose response curve for i.p. insulin.