Criteria of an experimental model analogous to type I human diabetes mellitus

ABSTRACT

Three doses of streptozotocin were given to adult male Boskat rabbits on 3 successive days as 20 mg/kg/day [i.v.]. The experimental follow up was extended to one month after completion of the treatment schedule. At the 14th day, there was a pronounced glucosuria in 100% of the treated animals with ketonuria in 67% of them. After 30 days, there was a marked rise in fasting plasma glucose [111%] associated with a marked reduction [51%] in plasma insulin activity with respect to the matched control group. Blood lactate showed 21% increase, but blood pyruvate was unchanged, while liver glycogen content was decreased by 30%. The radioimmunoassay of plasma growth hormone [GH] and glucagon revealed 57% and 20% increases in their levels, respectively, in the streptozotocin-treated rabbits. However, plasma cortisol was unchanged in comparison with the control group. The picomolar plasma ratios of GH, glucagon and cortisol in relation to insulin showed significant increases by 220%, 143% and 95%, respectively, in the diabetic animals with respect to normal. The overall pattern of results revealed a prototype of chemically-induced diabetes analogous to the human juvenile one and characterized by sustained hyperglycemia, insulinopenia, glucosuria and ketonuria. An additional merit of this model is the close similarity and overlapping between the estimated normal values of test parameters in Boskat rabbits and the reported corresponding human values, except in case of liver glycogen, plasma GH and cortisol