Insulin absorption from conjunctiva studied in normal and diabetic dogs

The dynamics of insulin absorption from the ocular conjunctiva of anaesthetized normal and pancreatectomized dogs have been examined. A porcine insulin preparation of 1000 units mL-1 (pH 8.0) was administered as either 1 or 10 units kg-1 to the upper conjunctival sacs of recumbent dogs following an overnight fast. Plasma insulin concentrations increased significantly at 5 min after the insulin administration. Plasma glucose concentrations decreased significantly, in both normal (given 10 units kg-1) and diabetic dogs (given 1 unit kg-1 or 10 units kg-1). There was a dose-dependent increase in plasma insulin concentration following conjunctival administration. Estimated absorption was significantly higher in diabetic than in normal dogs.