These results suggest that in the hospitalized normotensive NIDDM subjects, there are normal and reversed circadian MBP rhythms and that the reversal of normal circadian MBP rhythm may be related to the degree of postural hypotension and/or nephropathy.

Hyporeninemic hypoaldosteronism has been shown to occur in streptozotocin-induced chronic diabetic rats with normokalemia. To test the nature of the aldosterone deficiency, we investigated the responses of aldosterone production to angiotensin II (AII), ACTH, and potassium in adrenal zona glomerulosa cells from diabetic rats at 6 weeks after an injection of streptozotocin compared with those in the cells from control rats. In diabetic rats, plasma glucose was high and plasma immunoreactive insulin was low. Diabetic rats also had low levels of PRA and plasma AII, low levels of plasma aldosterone, and normal levels of plasma corticosterone and plasma potassium. The zona glomerulosa width was narrower in diabetic rats than in control rats. Basal aldosterone production, when corrected to an uniform number of cells per group, was similar in the cells from control and diabetic rats. Cells from diabetic rats showed a less sensitive and lower response of aldosterone production to AII, increases in the threshold and the ED50, and a decrease in the maximal AII-stimulated aldosterone level. ACTH, however, caused a similar effect on aldosterone production in the cells from control and diabetic rats. Cells from diabetic rats exhibited a less sensitive response of aldosterone production to potassium and a tendency to be low in the maximal potassium-stimulated aldosterone level, presumably attributable to the impairment of adrenal zona glomerulosa cells to AII. We conclude that the hypoaldosteronism observed in our diabetic rats may be secondary to the deficiency of AII.

To evaluate the heparin effects in vivo and in vitro on adrenal angiotensin II receptors and angiotensin II-induced aldosterone production, we examined the angiotensin II binding and the maximum angiotensin II-induced aldosterone production using adrenal glomerulosa cells from rats treated with a heparin preparation containing benzyl alcohol (1500 IU/kg, twice daily for 6 weeks) or cells to which heparin (300 IU/l) was directly added. Comparison was made using the cells from rats treated with vehicle or the cells to which vehicle was directly added. Specific binding of [125I]iodo-angiotensin II was decreased in the cells from heparin-treated rats or in the heparin-treated cells. Scatchard analysis showed that the decrease in binding was due to a decrease in both the number and the affinity of angiotensin II receptors in the cells from heparin-treated rats and a decrease in the number, but not the affinity, of the receptors in the heparin-treated cells. Heparin also caused a decrease in the maximum angiotensin Il-induced production, but not the basal production, of aldosterone in the cells from hepari n\x=req-\ treated rats and in the heparin-treated cells. These data suggest that heparin interacts with adrenal angiotensin II receptors to inhibit the angiotensin Il-induced aldosterone production.

Streptozotocin-induced chronic diabetic rats develop hyporeninemic hypoaldosteronism. The hypoaldosteronism is associated with selective unresponsiveness of aldosterone to angiotensin II (AII) and an atrophy of the zona glomerulosa. To assess the nature of the adrenal unresponsiveness to AII, we examined the [125I]monoiodoAII binding and the responses of pregnenolone formation and aldosterone production to AII using adrenal glomerulosa cells from diabetic rats 6 weeks after an injection of streptozotocin. Comparisons were made using the cells from control rats treated with vehicle. Diabetic rats had low levels of plasma renin activity, plasma 18-hydroxycorticosterone, and plasma aldosterone, and normal levels of plasma corticosterone and plasma potassium. The zona glomerulosa width was narrower in diabetic than in control rats. Scatchard analysis of the AII binding data demonstrated that the number and affinity of the receptors were similar in the cells from control and diabetic rats. When corrected to an uniform number of cells per group, baseline levels of pregnenolone formation and aldosterone production were similar in the cells from control and diabetic rats. However, cells from diabetic rats had a less sensitive and lower response of both pregnenolone formation and aldosterone production to AII. In contrast, the effect of ACTH on pregnenolone formation and aldosterone production was similar in the cells from control and diabetic rats. These results indicate that the main defect responsible for the hypoaldosteronism may be located on some step(s) mediating between AII receptors and conversion of cholesterol to pregnenolone, presumably on the calcium messenger system, with a disturbance downstream from AII binding.

Changes in TSH-receptor antibody (TR-Ab) and thyroid stimulating antibody (TS-Ab) after thyroidectomy were examined in seventeen thyrotoxic patients (3 males and 14 females, 40.0 +/- 3.4 yr) with positive TR-Ab and TS-Ab. They were subjected to thyroid surgery because of suspected malignancy, methymazol induced agranulocytosis, cardiac failure, recurrent gastric ulcer or emotional instability. Of these patients, 3 were totally thyroidectomized, 11 were subtotally thyroidectomized and 3 were unilaterally lobectomized. Histological findings in these patients showed diffuse hyperplasia in 8 cases, an adenomatous goiter in 3, diffuse hyperplasia plus follicular adenomas in 5, and Hashitoxicosis in one. Their thyroid function before surgery was as follows: T3 level, 3.9 +/- 0.7 ng/ml; T4, 19.5 +/- 3.3 micrograms/dl; free T3, 11.9 +/- 1.2 pg/ml; free T4, 4.9 +/- 1.0 ng/dl; and TSH, 0.9 +/- 0.1 microU/ml. Mean levels of TR-Ab and TS-Ab before surgery were 56.8 +/- 4.6% and 1,218.6 +/- 262.4%, respectively. Positive anti-thyroid antibody (TGHA) was 47.0%, positive anti-microsomal antibody (MCHA) was 88.2% in these thyrotoxic patients, and mean levels of TGHA and MCHA were 1,688 +/- 715 and 89,280 +/- 34,717 times, respectively. After the operation, these parameters were decreased and their thyroid functions became an euthyroid or a hypothyroid state one month later. The incidence of post-operative hypothyroidism was 45.5% in subtotally thyroidectomized patients, 33.3% in unilaterally lobectomized patients and 100% in totally thyroidectomized patients. TR-Ab levels decreased from 56.2 +/- 6.5% before surgery to 24.5 +/- 12.2% 12 months after surgery, but increased again to 35.0 +/- 15.7% 24 months after surgery in subtotally thyroidectomized patients. These levels also decreased from 50.4 +/- 11.0% before surgery to 37.8 +/- 11.4% 12 months after surgery, and remained unchanged to 38.2 +/- 10.4% 24 months after surgery in unilaterally lobectomized patients. On the other hand, in totally thyroidectomized patients, TR-Ab levels decreased and normalized 12 months after surgery. One of subtotally thyroidectomized or unilaterally lobectomized patients developed recurrent thyrotoxicosis with an increased positive TR-Ab. Mean levels of TS-Ab decreased to 28.3 +/- 181.3% and 152.5 +/- 47.9% 12 and 24 months after surgery, respectively, in subtotally thyroidectomized patients. These levels decreased 12 months after surgery and then increased again to 303.6 +/- 130.6% in unilaterally lobectomized patients. On the other hand, TS-Ab levels decreased and normalized to 94.3 +/- 3.9% 6 months after surgery in totally thyroidectomized patients.(ABSTRACT TRUNCATED AT 400 WORDS)