[Behavior of aldosterone and plasma renin activity after ACTH administration and insulin-induced hypoglycemia in patients with essential arterial hypertension]. / Comportamento dell'aldosterone e dell'attività reninica plasmatica dopo ACTH e ipoglicemia insulinica in pazienti con ipertensione arteriosa essenziale.

The response of plasma aldosterone (PA) and plasma renin activity (PRA) to ACTH stimulation (0.25 mg Tetracosactide infusion/10 h) and to insulin-induced hypoglycemia (0.1 U/kg b.w.) has been studied in 34 essential hypertensive (EH) patients. Corticotrophin stimulation increases significantly PA, the percent increase being higher in normal PRA EH patients than in controls but comparable to controls in low PRA EH patients. PRA shows a slight and transient elevation. A significant increase in PA is observed also during the insulin test, but the percent increase is lower than that under ACTH stimulation. The possibility that aldosterone is involved, under severe and frequent stress, in the genesis of essential hypertension is discussed.

18-hydroxy-11-deoxycorticosterone response to ACTH, insulin and furosemide administration in essential hypertensive patients.

Investigations were carried out on the behavior of 18-hydroxy-11-deoxycorticosterone (18-OH-DOC) in essential hypertension (EH) under exogenous administration of synthetic ACTH and insulin. 40 stable EH patients and 21 normal subjects were included in the study. The increase (12-fold basal values) in plasma 18-OH-DOC in normal subjects under Tetracosactide was significantly higher than cortisol (4-fold basal values). Furthermore, insulin hypoglycemia increased 18-OH-DOC levels 5-fold, whilst basal values of cortisol were increased 2-fold. An increase in 18-OH-DOC and cortisol was also observed in EH patients: in the subgroup with normal and low plasma renin activity, however, the rise in these two steroids was significantly lower than in normal subjects both under Tetracosactide and insulin. No significant hormonal modifications were observed after furosemide administration either in the normal subjects or in the EH patients. 18-OH-DOC by itself does not, therefore, appear to play a pathogenetic role in EH.

18-Hydroxy-11-deoxycorticosterone in hypertensive uremic patients during hemodialysis.

The present study was carried out in 25 hypertensive uremic patients on regular 4 h dialysis, 3 times a week. Plasma 18-hydroxy-11-deoxycorticosterone (18-OH-DOC), aldosterone (PA) and corticosteroids were determined by radioimmunoassay and competitive protein binding technique before and at the end of the 1st, 2nd and 3rd hour of hemodialysis. Plasma 18-HD-DOC was normal before dialysis and did not change significantly during hemodialysis, whereas body fluids and electolytes decreased progressively. No correlation was observed between blood pressure and 18-OH-DOC during dialysis. 18-OH-DOC did not correlate with PA which decreases progressively during hemodialysis and was correlated to plasma corticosteroids only at the 3rd hour of dialysis, probably on account of the enhanced influence of ACTH on the adrenal cortex.

Diurnal 18-hydroxy-11-deoxycorticosterone pattern in human stable hypertension.

Diurnal 18-hydroxy-11-deoxycorticosterone (18-OH-DOC) pattern was studied with RIA technique in 33 hypertensive patients in supine position and on normal sodium diet. The compound was evaluated every 2 h from 0800-2000 h. Simultaneously, plasma aldosterone and cortisol were measured. Abnormal 18-OH-DOC behavior was observed in only 2 out of 4 patients with Cushing's disease, while sporadic and slight elevations, synchronous with F, were seen in 5 out of 24 stable essential hypertensive patients [1 with normal plasma renin activity (PRA), 1 with low PRA, and 3 with high PRA]. 18-OH-DOC was normal in 2 cases of hypertension due to renal artery stenosis, in 1 patient with nephrosclerosis, and in 1 patient with horseshoe kidney. From these results, 18-OH-DOC does not seem to play an important pathogenetic role in stable essential hypertension, considering also the low mineralocorticoid activity of the compound.

24 hour profile of 18-hydroxy-11-deoxycorticosterone in normal supine man: relationship with cortisol and aldosterone.

Daily profiles of plasma 18-hydroxy-11-deoxycorticosterone (18-OH-DOC) were studied in four normal supine men on a normal sodium intake. Blood was taken every hour from 01.00 to 24.00 hours. Plasma cortisol (F) and aldosterone (A) were determined hourly for comparative studies. 18-OH-DOC fluctuated considerably during the 24 h period of investigation, the highest values being found during the early morning hours in synchrony with F. The episodic secretions of 18-OH-DOC were also significantly correlated with those of A, which in turn paralleled those of F. We conclude that ACTH, plays a definite role in the regulation of 18-OH-DOC in normal supine men on a normal sodium diet.

Behaviour of plasma renin activity and aldosterone during the first 72 h of life.

Plasma renin activity (PRA) and plasma aldosterone concentrations (PAC) were determined in fifty normal newborns during the first 72 h of life. PRA was elevated in all cases and tends to increase from the first (6.79 +/- 0.69SE ng/ml/h) to the third day of life (8.24 +/- 0.96SE ng/ml/h). PAC was also elevated and rose from 24.06 +/- 3.23SE ng/dl on the first day to 39.20 +/- 4.25SE ng/dl on the third day. No significant correlation was observed between PRA and PAC. Serum sodium was within the normal range, whereas serum potassium was slightly elevated during the first 48 h of life. The physiological significance of the high levels of PRA and PAC in newborns is not clear at present. Many factors may be involved in the increased activation of the renin-angiotensin-aldosterone system: low blood pressure, hypersensitivity of the macula densa to catecholamines, relative insensitivity of the immature kidney to aldosterone, hyperkalaemia and other control mechanisms for aldosterone secretion all of which probably operate simultaneously during the first days of life.

Prolactinemia during hemodialysis: lack of correlation with sodium, potassium and renin-aldosterone system.

The present investigation was carried out on 17 male patients, 2 of whom nephrectomized, affected by terminal renal failure on regular 4 h dialysis three times a week. Plasma prolactin (PRL), aldosterone (PA) and renin activity (PRA) were determined by radioimmunoassay before, and after the 1st, 2nd and 3rd h of hemodialysis. High levels of PRL were found in 9 nonnephrectomized patients; during the 1st and 2nd h of dialysis means values of PRL showed a slight tendency to increase, whilst during the 3rd h values decreased to predialysis concentrations. In one case a fall in PRL levels immediately after nephrectomy was observed but in another patient who came to our attention after surgery, PRL was significantly increased with values higher than those usually found in nonnephrectomized patients. PRA was elevated in 10 patients and showed no significant modifications during hemodialysis. PAC was high in 8 patients and decreased significantly during hemodialysis. A drop in sodium and potassium levels and a decrease in body weight during dialysis were also observed. These results suggest that in uremia the high levels of PRL are not consequent to hydroelectrolyte disorders or to a condition of hyperaldosteronism, since these parameters present a different pattern during hemodialysis.