Effects of tolbutamide on insulin binding to isolated fat cells of the rat

In isolated fat cells of the rat the in vitro and in vivo effects of tolbutamide on insulin binding and insulin response were studied. 450 mg tolbutamide/kg/day given for 7 days significantly increased the binding of insulin to isolated adipocytes. The binding curves reflected an increase in the number of receptor sites rater than in the affinity. The effect was associated with an enhanced response to insulin of the adipose tissue, since the fat cells obtained from animals treated with tolbutamide converted significantly more glucose to lipids in the presence of insulin than those obtained from the control group. However, the augmentation of insulin binding sites was observed only at a large tolbutamide dosage, which reduced the pancreatic insulin content, the secretory response of the isolated pancreas, and the serum insulin levels. Smaller doses, sufficient to produce metabolic effects via a stimulation of insulin secretion, did not provide additional insulin binding sites. When added in vitro to the binding assay or to adipose tissue incubated for 16 h, tolbutamide failed to increase insulin binding of the fat cells. It is suggested, therefore, that the effects produced by tolbutamide after in vivo treatment reflect an indirect rather than a direct action of the sulphonylurea.     

Plasma exchange in rapidly progressive glomerulonephritis (author's transl)

The combination of plasma exchange and immunosuppression appears to result in considerable improvement of therapeutic measures in rapidly progressive glomerulonephritis. In contrast to the unfavourable prognosis prior to the introduction of plasma exchange, 8 out of 13 patients (idiopathic rapidly progressive glomerulonephritis, n = 4; Goodpasture syndrome, n = 2; Wegener's granulomatosis, n = 4; lupoid nephritis, n = 3) showed recompensation of terminal renal insufficiency. Treatment of 4 patients who were already anuric led to reversal of renal function in only one case. There was a clear correlation between demonstration of circulating immune complexes and the response to treatment: in 6 out of 7 patients with circulating immune complexes recompensation of severe renal insufficiency was achieved.