- Polymer matrices containing insulin and embedded magnets were implanted subcutaneously in diabetic rats for 51 days. Passive release of insulin from the polymer resulted in a decrease in the blood glucose level. When the diabetic rats were exposed to an oscillating magnetic field, the blood glucose levels were additionally lowered by nearly 30%. No statistically significant effect in blood glucose decrease was observed in four different sets of control animals subjected to the magnetic field. Because of the very small size of the implants, they may, with additional study, provide an alternative to current modes of therapy using programmable implantable infusion pumps.