Reduction in [ 3H]-corticosterone binding to cytoplasmic receptors in the brain of diabetic rats

Abstract

The binding of [1, 2, 6, 7- 3H]-corticosterone was studied in brain cytosol from normal and streptozotocin-diabetic male rats. The experiments were performed under conditions of incubation time (4h), temperature (0–4°C), time after adrenalectomy (6 days) and corticosterone concentrations (1.2 × 10 −8 and 1.15 × 10 −9M) previously established for determining binding activity in the brain of normal rats. The binding of [ 3H]-corticosterone was found invariably lower in cytosol of the brain from diabetic rats, studied under three different conditions: in non-adrenalectomized animals, in adrenalectomized using a non-saturating corticosterone concentration, and in adrenalectomized plus a saturating steroid concentration. These results support previous contentions that the diminished sensitivity to the negative feedback for steroids which is present in diabetics, may be related to a reduction in binding capacity for corticoids in the central nervous system