The difference between the initial and minimum glucose concentrations achieved during the administration of different forms of insulin was 95 ± 12, 53 ± 11 and 98 ± 19 mg/dL, for normal rabbits, and 304 ± 26, 488 ± 68 and 532 ± 57 mg/dL for rabbits with diabetes for the free form, administered intravenously and subcutaneously, and for insulin in RBCs, respectively. Here, INS is linked to diabetes mellitus.