ALDOSTERONE BINDING TO MINERALOCORTICOID RECEPTORS OF MONONUCLEAR LEUKOCYTES IN DIABETIC SUBJECTS

We present the characteristic features of mineralocorticoid receptor r egulation in human mononuclear leukocytes in patients with diabetes me llitus. Eighteen diabetic patients (3M and 15F, aged from 28 to 77 yea rs with a mean of 53 +/- 14 (mean +/- SD) years) and 7 normal subjects (6M and 1F, aged from 29 to 59 years with a mean of 41 +/- 13 years) were studied. The mean plasma aldosterone concentration in the diabeti c patients was significantly lower than that in the normal subjects (1 37 +/- 62 vs 189 +/- 36 pmol/l, p < 0.05). Seven of the 18 diabetic pa tients were hypoaldosteronemic. These 7 patients, however, showed norm okalemia, except one with mild hyperpotassemia. The number of binding sites of [H-3]aldosterone to mineralocorticoid receptor in the diabeti c patients was significantly higher than that in the normal subjects ( 853 +/- 281 vs 488 +/- 109 sites/cell, p < 0.0 5), but there was no si gnificant difference in K(d) of [H-3]aldosterone binding to mineraloco rticoid receptor between the diabetic patients and normal subjects (1. 34 +/- 0.3 7 vs 0.99 +/- 0.61 nmol/l). In the diabetic patients, a sig nificant negative correlation was observed (r = 0.70, p < 0.01) betwee n plasma aldosterone concentration and the binding sites, but not betw een plasma aldosterone concentration and K(d). In the total subjects, including normal subjects and diabetic patients, a significant negativ e correlation was also found between plasma aldosterone concentration and binding sites (r = 0. 72, p < 0.00 1). These results suggest that increased binding sites of mineralocorticoid receptor may help to prev ent diabetic patients from being hyperkalemic.