Immunologic Insulin Resistance

The efficacy of sulfated beef insulin for plasma glucose control in 35 patients with immunologie insulin resistance was studied. Patients were on a mean dose of 550 U./day (range 200–2,000) of U-500 regular beef insulin. Mean maximum 125I-insulin-binding capacity was 191 mU./ml. serum (range 13–1,080). Mean in vivo half-life (T½) of 125I-regular beef insulin was 614 minutes (range 114–1,300), as against a mean T½ of 13.9 minutes (range 11.8–16.5) in normal controls. Treatment was successful in 34 patients and unsuccessful in one with lipoatrophic diabetes. The mean initial dose of sulfated insulin was 89 U./day (range 15–400) and at three months was 66 U./day (range 20–400). Twenty-eight patients who responded and survived have been on sulfated insulin for a mean of 39 months (range 2–66) and are on a mean dose of 25 U./day (range 0–100). The mean maximum binding capacity fell to 9 mU./ml. (range 0–34) during therapy (p<0.01). Mean 125I-insulin T½ fell from 614 to 249 minutes after sulfated insulin therapy (p<0.001). A comparative study of 15 patients on consecutive days showed a 35sulfated insulin T½ of 60 minutes (range 15–94) and a mean 125I-regular insulin T½ of 246 minutes (range 62–560, p<0.001). These results indicate that sulfated insulin is less antigenic than regular beef insulin and combines less avidly with human antibodies to regular beef insulin. The response to sulfated insulin therapy was significantly better than the response reported by other investigators to pork insulin or to steroid therapy in similar patients.