[The hypothalamo-hypophyseal system: the role of calcium ions]. / Sistema diencefalo ipofisario: ruolo dei calcio ioni.

The Authors investigated the effects of Verapamil a calcium antagonist substance upon the pituitary response to several secretogogus agents in ten male healthy subjects in order to elucidate the calcium role in the regulation of the hypothalamic pituitary function. As a consequence of Verapamil administration (5 mg iv) a significant hyporesponsiveness of FSH and LH to GnRH (100 micrograms iv) of TSH to TRH (200 gamma iv) and of ACTH to insulin induced hypoglycemia was observed. Prolactin response to TRH (200 gamma iv) was not modified by Verapamil treatment. The Authors concluded emphasizing the importance of Ca++ in the modulation of diencephalic pituitary activity.

[The vasoactive effects of captopril (SQ 14225). Preliminary research]. / Effetti vasoattivi del captopril (SQ 14225). Ricerche preliminari.

The Authors examined the behaviour of the humeral arterial pressure, of the heart frequency and of the muscular blood flow in inferior limbs. This study was performed before and after treatment with Captopril (SQ 14225), 100 mg per os, a selective inhibitor of the converting enzyme. Both resting blood flow (RBF) and maximal blood flow (NBF) were studied by Xenon 133 clearance. The A.A. observed that the drug induced a significant (P less than 0.01) increase of both RBF and MBF. Therefore, the Authors hypothesize that the Captopril is able to produce peripheral vasodilatation, without any significant variation of the cardiac index and frequency. Such an effect is considered to depend not only upon the inhibited angiotensin II production, but also upon stimulation of bradikinins and prostaglandins.

[The dopaminergic system and aldosterone secretion. I. Suppressive effects of L-dopa on secondary hyperaldosteronism]. / Sistema dopaminergico e secrezione di aldosterone. Nota I. Effetti soppressivi della L-dopa sull'ipera dosteronismo secondario.

The authors studied the blood aldosterone, cortisol and kalium levels, the plasma renin activity and the aldosterone urinary excretion following L-DOPA (0.50 g per os) administration in seven patients affected by hypertension and secondary hyperaldosteronism. The results suggest that L-DOPA administration, by stimulating the dopaminergic biosynthesis. Nevertheless such a conclusion needs further investigations.

[The dopaminergic system and aldosterone secretion. II. Effect of L-dopa and dexamethasone on aldosterone biosynthesis]. / Sistema dopaminergico e secrezione di aldosterone. Nota II. Effetti della L-dopa e del desametazone sull'aldosteronogenesi.

The authors studied the blood aldosterone, cortisol, and kalium levels, the plasma renin activity and the aldosterone urinary excretion following L-Dopa (0,50 g per os) administration in five patients affected by hypertension and six healthy control subjects, before and after the CRF-ACTH system suppression. The observed pattern shows that the aldosterone biosynthesis is inhibited also after the CRF-ACTH system has been suppressed. Therefore the authors conclude that the inhibiting action of L-Dopa on the aldosterone biosynthesis is mediated by the dopaminergic system stimulation.

[Saralasin in subjects with low renin arterial hypertension]. / Saralasina ed ipertensione arteriosa a bassa reninemia.

The Authors have studied, in a group of hypertensive subjects with low renin, the behavior of arterial blood pressure, PRA, plasma aldosterone, plasma K and Na, after intravenous load of Saralasin before and after treatment with Furosmide (40 mg orally given for 4 days). In such conditions we evidenced an agonist effect of Saralasin mainly on plasma aldosterone and less on arterial pressure. The Authors conclude that Saralasin, in given conditions (free receptor sites), can exhibit on agonist effect on aldosterone secretion; such agonist effect can be augmented by dopaminergic deficit, that sometimes in present is essential arterial hypertension.

[Aldosterone production in vitro by angiotensin II: the role of Ca++]. / Produzione di aldosterone in vitro da angiotensina II: ruolo de Ca++.

In beef isolated and superfused adrenal glands, the Authors have studied the production of aldosteron and tissue concentration of cAMP during superfusion with angiotensin II alone or preceededby preincubation with indomethacin or verapamil. In such experimental conditions the Authors could evidence that th aldosterone-inductor effect of angiotensin II is not mediated by cAMP but by PGs and Ca++.

[Histological and ultrastructural studies on liver of rats treated with tiadenol]. / Ricerche istologiche ed ultrastrutturali sul fegato di ratti trattati con tiadenolo.

By hystological and electronmicroscopical study liver of rats treated with tiadenol at a daily dose of 100 and 200 mg for 30 days, we could demonstrate: lack of necrosis and interstitial phlogosis and, especially in those animals treated with greater doses, numerical increase of peroxisomes, hypertrophy of SER and RER and a lesser regularity of glycogen distribution.

Effect of prostaglandin A on renin secretion in the dog.

The role of PGA on the release of renin in the anesthetized dog has been studied. The infusion of prostaglandin for 60 minutes at a dose unable to cause pressor modifications (2 microgram/kg/min) was shown to increase the plasma renin activity (PRA); this effect was inhibited by propranolol and strengthened by aminophylline.