We present the characteristic features of mineralocorticoid receptor regulation in human mononuclear leukocytes in patients with diabetes mellitus. Eighteen diabetic patients (3M and 15F, aged from 28 to 77 years with a mean of 53±14 (mean±sd) years) and 7 normal subjects (6M and IF, aged from 29 to 59 years with a mean of 41±13 years) were studied. The mean plasma aldosterone concentration in the diabetic patients was significantly lower than that in the normal subjects (137±62 vs 189±36 pmol/l, p<0.05). Seven of the 18 diabetic patients were hypoaldosteronemic. These 7 patients, however, showed normokalemia, except one with mild hyperpotassemia. The number of binding sites of [3H]aldosterone to mineralocorticoid receptor in the diabetic patients was significantly higher than that in the normal subjects (853±281 vs 488±109 sites/cell, p<0.05), but there was no significant difference in Kd of [3H]aldosterone binding to mineralocorticoid receptor between the diabetic patients and normal subjects (1.34±0.37 vs 0.99±0.61 nmol/l). In the diabetic patients, a significant negative correlation was observed (r=0.70, p<0.01) between plasma aldosterone concentration and the binding sites, but not between plasma aldosterone concentration and Kd. In the total subjects, including normal subjects and diabetic patients, a significant negative correlation was also found between plasma aldosterone concentration and binding sites (r=0.72, p<0.001). These results suggest that increased binding sites of mineralocorticoid receptor may help to prevent diabetic patients from being hyperkalemic.
Takeshi Shimada, Keigo Yasuda, Akihiro Mori, Huiping Ni, Leilani B Mercado-Asis, Hiroshi Murase and Kiyoshi Miura
Noriko Kojima, Shigeki Sakata, Shigenori Nakamura, Keita Kamikubo, Makio Okuyama and Kiyoshi Miura
Abstract. Serum concentrations of thyroxine binding globulin (TBG) were measured in healthy adult subjects aged 20–79 years (152 males and 148 females) by radioimmunoassay.
In contrast to previous reports, there were no significant age-related differences in either sex. Significant sexrelated differences were observed only in the fourth decade, being higher in females than males (P < 0.01).
Noriyoshi Yamakita, Keigo Yasuda, Nobuyasu Noritake, Leilani B. Mercado-Asis, Hiroshi Murase, Tomoatsu Mune, Hiroyuki Morita and Kiyoshi Miura
The clinical and endocrine characteristics of 12 Japanese patients with dexamethasone-suppressible hyperaldosteronism were compared with those in 49 Japanese patients with primary aldosteronism due to aldosteronoma. The results were as follows: 1. Most of the laboratory data in the two groups were almost the same. 2. The grade of vascular damage in both uncontrolled (3) and well-controlled (9) patients with dexamethasonesuppressible hyperaldosteronism did not correlate with blood pressure response. 3. The responsiveness of plasma aldosterone to exogenous ACTH in 6 patients with dexamethasone-suppressible hyperaldosteronism was not different from that in 9 patients with aldosteronoma. Even in 3 well-controlled patients in the former group, the plasma aldosterone response was as low as in all the 3 patients with small aldosteronomas. 4. In 4 patients with small aldosteronomas, plasma aldosterone was continuously suppressed with daily dexamethasone to the same degree as in dexamethasone-suppressible hyperaldosteronism. 5. The blood pressure, however, did not improve even in the patients with small aldosteronomas. The possible indistinguishable mechanism in dexamethasone-suppressible hyperaldosteronism and primary aldosteronism with small adenomas and the role of unknown hypertensinogenic steroid(s) other than aldosterone in inducing hypertension in dexamethasone-suppressible hyperaldosteronism are discussed.