Correlation between minimal secretory capacity of pancreatic beta-cells and stability of diabetic control.

The significance of the minimal secretory capacity of pancreatic beta-cells for the stability of the plasma glucose level was studied in 20 patients with insulin-dependent diabetes mellitus. Changes in plasma concentrations of major counterregulatory hormones in response to hypoglycemia were also investigated in these patients to clarify their contribution to diabetic brittleness. beta-Cell function was evaluated on the basis of elevation of plasma C-peptide immunoreactivity (CPR) during the intravenous glucagon test with a highly sensitive assay for plasma CPR that could detect as little as 0.03 ng/ml. After stimulation with glucagon, a significant increase in plasma CPR was observed in 10 of the patients whose beta-cell function had been evaluated as completely depleted by a conventional assay for plasma CPR. A clear inverse correlation was found between the secretory capacity of pancreatic beta-cells measured in this way and the degree of glycemic instability (r = -.74, P less than .01). Infusion of insulin at a rate of 0.15 U.kg-1.h-1 for 60 min caused a continuous decrease in the plasma glucose level, resulting in neuroglycopenia in 7 of the 10 CPR nonresponders but only 2 of the CPR responders. During insulin-induced hypoglycemia, plasma glucagon immunoreactivity did not increase in the CPR nonresponders but increased significantly in the CPR responders. A positive correlation was found between the minimal residual beta-cell capacity and the responsiveness of alpha-cells to hypoglycemia (r = .65, P less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Familial Bartter's syndrome.

Two sisters were found to have Bartter's syndrome. Both had hypokalemia, hyperreninemia, normal BPs, and decreased pressor responses to angiotensin II. During a water diuresis, patient 1 had an abnormally low distal tubular fractional reabsorption of chloride initially, but this normalized after hypokalemia was corrected for one year. Patient 2 had no demonstrable defect in chloride transport. Hypokalemia in Bartter's syndrome may be caused by some hereditary mechanisms other than defective reabsorption of chloride in the distal tubules.

Effects of nitrates and calcium channel blockers on Ca2+-ATPase in the microsomal fraction of porcine coronary artery smooth muscle cells.

The effects of the antianginal drugs nitroglycerin, nicorandil, diltiazem, verapamil and nicardipine on the activity of calcium-stimulated magnesium-dependent ATPase (Ca2+-ATPase) were investigated in the microsomal fraction from porcine coronary artery smooth muscle cells. Two discrete Ca2+-dependent ATPase components were observed: [1] a high affinity component, which was a specific Ca2+-ATPase, [with a half saturation constant for Ca2+ (Km) of 0.44 microM, and maximum velocity (Vmax) of 124.3 pmol of phosphate (Pi) released/micrograms of protein/30 min]: [2] a low affinity component in which Ca2+ could be replaced by Mg2+ without loss of its activity. Nitroglycerin and nicorandil (1 microM and 10 microM) both stimulated the activity of the Ca2+-ATPase significantly [142 +/- 12 (mean +/- standard error), and 137 +/- 10% of the control with nitroglycerin, and 152 +/- 17 and 135 +/- 20% with nicorandil] at a Ca2+ concentration of 0.3 microM. Diltiazem, verapamil and nicardipine did not cause significant stimulation. Nitroglycerin and nicorandil (1 microM), significantly decreased the Km for Ca2+ from the control value of 0.44 +/- 0.06 microM to 0.26 +/- 0.03 and 0.22 +/- 0.03 microM, respectively. Nitroglycerin and nicorandil may dilate coronary arteries by stimulating this Ca2+ extrusion pump enzyme through reduction of intracellular Ca2+ in smooth muscle cells.

Differentiation of pseudo- and idiopathic hypoparathyroidism by measuring urinary calcitonin.

Calcitonin (CT) levels were determined in urine specimens from normal subjects and patients with pseudohypoparathyroidism type I (PHP), idiopathic hypoparathyroidism (IHP), pseudopseudohypoparathyroidism (PPHP), and surgical hypoparathyroidism (SHP). Urinary CT was measured by RIA after extraction of urine by gel chromatography on a 0.8 X 20-cm column of Bio-Gel P-2. The urinary CT level ranged from 420-1000 pg/mg creatinine (Cr; mean +/- SD, 631 +/- 229) in PHP (n = 6), from 50-270 (131 +/- 92) in IHP (n = 6), and from 35-93 (66 +/- 27) in SHP (n = 6), and was 185 pg/mg Cr in one patient with PPHP. The mean value in PHP was significantly (P less than 0.001) higher, and that in SHP was significantly (P less than 0.05) lower, than those in the age-matched normal subjects. In each patient with PHP and IHP before and after treatment with 1 alpha-hydroxycholecalciferol, urinary CT levels fluctuated between 700-1370 pg/mg Cr in PHP and from 43-195 pg/mg Cr in IHP. Increased urinary excretion of CT in patients with PHP suggests that CT secretion may be enhanced in this disease. The biological role of CT in PHP remains to be clarified.

Effect of clomiphene on basal and LRH-induced gonadotropin secretion in postmenopausal women.

LRH tests were performed in 11 postmenopausal women before and after the administration of 200 mg of clomiphene citrate daily by mouth for 7 consecutive days. The basal levels and the maximum increments of serum LH (deltaLH) and the area under the response curve from basal level (deltaarea) after LRH administration, significantly (P less than 0.005) decreased after consecutive administration of this compound. Serum FSH levels were significantly (P less than 0.025) decreased but deltaFSH and deltaarea in LRH test were statistically unchanged. These results suggest that clomiphene citrate in postmenopausal women inhibits the pituitary gonadotropin response to exogenous LRH by its estrogenic effects.

Plasma norepinephrine and dietary sodium intake in normal subjects and patients with essential hypertension.

To evaluate the relationship between sodium intake and the activity of the sympathetic nervous system in patients with essential hypertension, plasma catecholamine levels were measured in 49 essential hypertensive patients and 38 age-matched normal subjects under regular-, high-, and low-sodium diets (mean 24-hour sodium excretions; 116 +/- 8, 267 +/- 29, 31 +/- 7 mEq/day, respectively). The levels of plasma norepinephrine were significantly (p less than 0.01) higher in hypertensive patients than in normal subjects. However, they were significantly reduced by high-sodium intake and increased by low-sodium intake in both patients and controls. The percent decrease and change in the absolute plasma norepinephrine levels from low- to high-sodium states were greater in normal subjects than in the hypertensive patients. The results are interpreted as indicating that an abnormal relationship exists between sodium intake and the activity of sympathetic nervous system in patients with essential hypertension.

Increased plasma norepinephrine in young patients with essential hypertension under three sodium intakes.

Increased sympathetic nerve activity may play an important role in the pathogenesis of essential hypertension. It is well known that both dietary sodium intake and age influence the plasma norepinephrine (NE) concentration. The present study was undertaken to evaluate the effects of age on sympathetic nerve activity in patients with essential hypertension and normal control subjects under low-, regular-, and high-sodium regimens (mean 24-hour sodium excretions: 30 +/- 4, 116 +/- 7,280 +/- 15 mEq, respectively). Plasma NE and epinephrine (E) were analyzed by trihydroxyindole methods after high-performance liquid chromatography separation. Subjects were categorized by age into young (less than or equal to 40 yrs), middle-aged (40-60 years), and old (greater than or equal to 60 years) subgroups. Mean plasma NE in hypertensive patients was significantly higher (p less than 0.01) than in normal subjects on each of the sodium regimens. In normal control subjects, there was a significant positive correlation between age and plasma NE with all three sodium intakes. However, no correlation was seen in hypertensive patients on any of the sodium regimens, because in the young subgroup of hypertensive patients the mean plasma NE was significantly higher than that of normal control subjects. These results suggest that the increased sympathetic nerve activity plays an important role in the pathogenesis of essential hypertension, especially in young patients.

Role of acetyl glyceryl ether phosphorylcholine in blood pressure regulation in rats.

The role of an endogenously occurring acetyl glyceryl ether phosphorylcholine (AGEPC) in blood pressure regulation was studied with an AGEPC antagonist in rats with hypertension of various etiologies. The hypotensive activity of an intravenously injected AGEPC was competitively suppressed by the intravenous infusion of 3-(N-n-octadecylcarbamoyloxy)-2-methoxypropyl-2-thiazolioethylphospha te (CV-3988) and was dose-dependent. The CV-3988 was infused intravenously into one- and two-kidney, one clip hypertensive, deoxycorticosterone-salt hypertensive, adrenal regeneration hypertensive, spontaneously hypertensive, and normotensive control rats. The increase in blood pressure caused by CV-3988 infusion in spontaneously hypertensive and normotensive control rats was significant (p less than 0.01 and p less than 0.001, respectively, at 60 min) compared with that caused by vehicle infusion. The increase was not seen in rats with secondary hypertension. In rats with two-kidney, one clip hypertension, the initial rapid decrease in blood pressure seen after unclipping was significantly (p less than 0.05) inhibited by CV-3988 infusion as compared with that by vehicle infusion. These results suggest that endogenous AGEPC may participate in the blood pressure regulation and pathophysiology of some forms of hypertension in rats.

Serum thyroid hormones and thyrotropin in anorexia nervosa.

Sixteen patients with typical signs and symptoms of anorexia nervosa were studied with measurement of serum thyroxine (T4), triiodothyronine (T3) and thyrotropin (TSH), both baseline and stimulated by thyrotropin-releasing hormone (TRH). The results of the patients were compared with those of 16 normal control subjects. Serum T4 (5.8 plus or minus 0.26 mug/100 ml, mean plus or minus SE) and T3 (82 plus or minus 5.7 ng/100 ml) of patients with anorexia nervosa were significantly (P less than 0.001) lower than those of control subjects (T4 7.7 plus or minus 0.32 mug/100 ml and T3 158 plus or minus 4.7 ng/100 ml respectively). Furthermore, the ratio of T3/T4 (1.48 plus or minus 0.243 x 10(-2)) in anorexia nervosa was also lower than that of control subjects (2.21 plus or minus 0.093 x 10(-2)) (P less than 0.001). Basal serum TSH was within normal or below the limits of detection. TSH and T3 rose after administration of TRH. The peak values of TSH were observed after 60 to 12o min, instead of 30 min normally seen after TRH injection.

Exophthalmos in autoimmune thyroid disease.

Protrusion of the eyes of patients with autoimmune thyroid disease was compared with that of healthy subjects. The mean values for protrusion in patients with thyrotoxic Graves' disease and Hashimoto's disease and in healthy subjects were 16.6 +/- 2.1 mm (mean +/- SD; n = 122), 14.2 +/- 1.8 mm (n = 100), and 13.9 +/- 1.9 mm (n = 558), respectively. The value of Graves' disease was significantly different from that for healthy subjects (P < 0.001). Individual values for protrusion showed a similar normal distribution in these three groups, but were displaced to higher values as a whole in Graves' disease. These results, which suggest that almost all patients with Graves' disease have exophthalmos, do not support the idea that Graves' ophthalmopathy is a distinct single autoimmune disease.

Prolactin response to arginine in normal subjects and in patients with hyperthyroidism.

The effect of arginine on serum prolactin concentrations was studied in 18 normal subjects and in 7 patients with hyperthyroidism in normal subjects, arginine infusion produced an increase of serum prolactin at least 6 ng/ml from the baseline, and the mean peak level (25.2 +/- 3.3 ng/ml, mean +/- SE) was significantly higher than the basal level (8.6 +/- 5.2 ng/ml, P less than 0.001). There was no significant difference in the peak levels between sexes. Unlike prolactin, concomitant serum thyrotropin levels did not change after the arginine infusion. In hyperthyroid patients, the increment of serum prolactin after arginine infusion at 30 min (3.9 +/- 1.5 ng/ml) was significantly lower than that of the normal controls which were matched by age and sex (17.1 +/- 4.4 ng/ml, P less than 0.05). After treatment when these patients were euthyroid, the increment of prolactin after arginine infusion at 30 min was significantly increased (16.3 +/- 4.3 ng/ml, P less than 0.05) and had reached the level of control subjects. These data indicate that the prolactin response to arginine in hyperthyroidism is diminished.

LH and FSH response to synthetic LHRH after consecutive administration of clomiphene citrate in normal males.

LHRH tests (100 mug iv) were performed in 11 normal male volunteers before and after administration of 100 mg clomiphene citrate per os for 7 days. Serum FSH, both pre and post LHRH levels (peak value and area under response curve) were significantly increased (P less than 0.01) by clomiphene citrate, while the maximum increments of FSH above baseline (deltaFSH) and area under response curve from basal level (deltaarea) were unchanged. On the other hand, basal serum LH levels increased significantly (P less than 0.005), post LHRH levels did not change by clomiphene citrate, whereas the increments after LHRH administration (both deltaLH and deltaarea) decreased significantly (P less than 0.05) on the second LHRH test. Basal levels of testosterone increased following clomiphene citrate treatment (P less than 0.005). The increased testosterone is considered to suppress the effect of LHRH on LH secretion.

Comparison of short and long-term treatment with synthetic LH-releasing hormone and clomiphene citrate in male hypothalamic hypogonadism.

The effects of short and long-term treatment with clomiphene citrate and with synthetic LH-releasing hormone (LHRH) on gonadotropin release were studied in 5 male patients with hypothalamic hypogonadism. Neither short-term treatment with clomiphene citrate (50 mg or 200 mg daily for 4 days) nor long-term treatment (25 mg or 100 mg for 30-62 days) was effective in increasing serum LH and FSH in any patients. On the other hand, 5 cases showed slight or no rise in LH after administration of a single dose of 100 mug LH-releasing hormone (LHRH) and higher rises after administration of 400 mug. Four cases who were given 200 mug LHRH daily for 3 weeks showed an increasing response of serum LH and reached maximal LH levels at 2 weeks, followed by no further increase. In two of the four cases serum LH level reached normal adult male ranges. There was no increase of serum testosterone during LHRH treatment. These results suggest that long-term treatment with synthetic LHRH may be effective for gonadotropin restoration in some patients with hypothalamic hypogonadism in which long-term treatment of clomiphene citrate was shown to be ineffective.

Enzyme-labelled immunoassay for plasma cortisol.

An enzyme-labelled immunoassay for plasma cortisol was developed. For this alkaline-phosphatase was conjugated through 21-hemisuccinate of cortisol using water-soluble carbodiimide. An antibody was raised in rabbits against corisol-21-hemisuccinate bovine serum albumin. Before assay 10 mul samples of plasma were mixed with glutamate buffer, pH 3.3, and boiled to denature endogenous cortisol-binding globulin and alkaline-phosphatase. Separation of "bound and free" cortisol was done by the double antibody method. A linear relationship was obtained between the volume of plasma and the amount of cortisol. The minimal detectable level of plasma cortisol was 1 mug/dl and the coefficients of variation were 2.7%-4.4% (within assays) and 4.7%-6.0% (between assays). Cortisol values determined by the present method correlated well with those determined by radioimmunoassay. The present method of enzyme-labelled immunoassay is suitable for routine clinical analysis of plasma cortisol.

Blood pressure response to an angiotensin II antagonist in patients with acromegaly.

The renin-angiotensin-aldosterone system in patients with acromegaly was evaluated by infusing [sarcosine1, isoleucine8]angiotensin II, a competitive angiotensin II antagonist, into five acromegalic patients with hypertension and three normotensive acromegalics. The drug was infused at a rate of 600 ng/kg . min for 30 min, 1 h after iv injection of 40 mg furosemide. In addition, before the infusion, plasma samples were obtained for determination of PRA and plasma aldosterone concentration. A significant pressor response to [sarcosine1, isoleucine8]angiotensin II was observed in all eight patients. Preinfusion PRA and plasma aldosterone concentration were significantly lower than in normal controls. It is concluded that in acromegaly, the renin-angiotensin-aldosterone system is suppressed and that this system is probably not involved in maintenance of the high blood pressure observed in some acromegalic patients.

Vasoconstriction and hypersensitivity to vasoactive substances after acute volume expansion in dogs.

In a search for factors contributing to the sustained blood pressure (BP) elevation in acutely volume-loaded animals, dextran dissolved in lactated Ringer's solution (20 ml/kg) was infused into 34 mongrel dogs over a period of 1 hour under pentobarbital anesthesia and changes in hemodynamic and humoral variables were monitored during its infusion and for 3 hours after its infusion. BP elevation during volume loading (from 114 +/- 3 to 128 +/- 3 [SEM] mm Hg) was attributed to an increase in cardiac output. After volume loading, some dogs maintained BP elevation whereas others did not. The former group showed an increase in total peripheral resistance, demonstrating a transformation of cardiac output to total peripheral resistance as a responsible factor in maintenance of the elevated BP. The plasma levels of norepinephrine, vasopressin, and plasma renin activity were not elevated, indicating that these vasoactive factors were not responsible for elevation of the BP or total peripheral resistance. The changes in the hematocrit, atrial natriuretic factor, urine volume, and urinary sodium excretion were identical in the two groups, and natriuresis was not prominent when total peripheral resistance was high. Pressor responses to norepinephrine and angiotensin II were potentiated 3 hours after stopping infusion in both groups, but this potentiation was not correlated with the increase in total peripheral resistance or mean BP. Thus, acute volume expansion produced resistance-dependent hypertension following the initial volume-dependent hypertension. It is unlikely that a vascular sensitizing natriuretic factor plays a role in the resistance-dependent BP elevation. The mechanism and physiological importance of hypersensitivity to vasoactive substances remain to be elucidated.

Association of serum antithyroid antibodies with lymphocytic infiltration of the thyroid gland: studies of seventy autopsied cases.

Postmortem histological examination of the thyroid gland and measurement of serum antithyroid antibodies were performed in 70 patients without overt thyroid disease. Lymphocytic infiltration, antithyroglobulin hemagglutination antibody (TGHA), and antithyroid microsomal hemagglutination antibody (MCHA) were found in 12, 2, and 9 cases, respectively. The incidence of lymphocytic infiltration in females was three times that in males. Ten of the 12 cases with lymphocytic infiltration had positive antibodies (either TGHA or MCHA), while 10 of 11 patients with positive antibodies showed lymphocytic infiltration. Thus, the correlation between morphological and serological findings was highly significant at P less than 0.001. The incidence of a small thyroid gland of less than 15 g in weight was higher in patients with lymphocytic infiltration and/or positive antibodies than in patients with a normal thyroid gland. These data suggest that positive serum antithyroid antibodies in subjects without overt thyroid disease may indicate the existence of lymphocytic infiltration in the thyroid gland, that is presumably subclinical autoimmune thyroiditis.

Plasma inactive renin in patients with hyperthyroidism.

Active and inactive PRA were measured after 1 h at rest in 16 normal controls and 20 patients with hyperthyroidism. In some of the patients these measurements were repeated after they had become euthyroid or received 90 mg propranolol for 1 week. Inactive PRA was determined as the difference between total PRA after trypsin activation and active PRA. Active PRA was significantly higher (P less than 0.01) in untreated patients than in normal subjects; however, the inactive PRA of patients was not different compared with that of normal subjects. Active PRA was normalized, and inactive PRA did not change after achievement of euthyroidism. The proportion of active of total PRA was significantly correlated with the levels of serum thyroid hormones (T3 and T4) in hyperthyroid patients (r = 0.46; P less than 0.05 and r = 0.55; P less than 0.01, respectively). The administration of propranolol reduced active PRA (P less than 0.05) and increased inactive PRA slightly but not significantly. These results indicate that in hyperthyroidism, the in vivo conversion of inactive renin to active renin is probably facilitated by increased sympathetic activity.

T lymphocyte subsets in autoimmune thyroid diseases and subacute thyroiditis detected with monoclonal antibodies.

Peripheral T lymphocyte subsets were analysed with monoclonal antibodies, by highly standardized fluorescence-activated cell sorter analysis instead of manual counting by the indirect immunofluorescence method, in autoimmune thyroid diseases and subacute thyroiditis. Total lymphocyte counts were increased in patients with thyrotoxic Graves' disease and subacute thyroiditis. The percentage of total T (Leu 1) cells was significantly lower in patients with thyrotoxic Graves' disease and Hashimoto's disease with destructive thyrotoxicosis than in normal subjects. No significant changes were observed in the percentages of suppressor-cytotoxic T (Leu 2a) cells or helper-inducer T (Leu 3a) cells or in the Leu 3a-Leu 2a ratio in different groups of patients. There were no correlations between the percentages of E rosette-forming cells and Leu 1 cells and between the percentages of T gamma cells and Leu 2a cells in normal subjects and patients. The peak position of fluorescence intensity of Leu 2a cells showed a significant sex difference even in normal controls. The most important finding was a significant decrease in the peak position of Leu 2a cells in patients with thyrotoxic Graves' disease and with hypothyroid or thyrotoxic Hashimoto's disease. These findings indicate the significant association of qualitative, but not quantitative, abnormality of suppressor-cytotoxic T (Leu 2a) cells with thyroid dysfunction in autoimmune thyroid diseases.

Renin inhibitor and converting enzyme inhibitors suppress vascular angiotensin II.

The direct effects of a renin inhibitor, N-acetyl-pepstatin and five angiotensin converting enzyme inhibitors, captopril and the active diacid forms of enalapril, ramipril, cilazapril, and CS-622, on the vascular renin-angiotensin system were examined in isolated perfused rat mesenteric arteries. Vascular renin activity and angiotensin II (Ang II) released into the perfusate were determined. Infusion of N-acetyl-pepstatin (5 X 10(-8)-5 X 10(-6) M) suppressed vascular renin activity and Ang II release dose dependently. Isoproterenol (10(-6) M) induced a 135 +/- 30% increase in Ang II release from the basal value. N-Acetyl-pepstatin (5 X 10(-6) M) suppressed isoproterenol-induced Ang II release. Infusions of 5 X 10(-6) M captopril and the diacid forms of enalapril, ramipril, cilazapril, and CS-622 by themselves had little effect on Ang II release, but concomitant infusion of isoproterenol with these angiotensin converting enzyme inhibitors significantly decreased Ang II release (71 +/- 21%, 51 +/- 40%, 8 +/- 21%, 69 +/- 24%, and 44 +/- 29% increase, respectively, from the basal values). These results indicate that N-acetyl-pepstatin suppresses the vascular renin-angiotensin system. This effect may in part contribute to the hypotensive actions of renin inhibitors. Although angiotensin converting enzyme inhibitors also suppress locally generated Ang II, the mechanism and physiological significance still remain to be clarified.