Water intoxication mostly occurs in psychiatric patients. We observed 13 episodes of severe hyponatremia (less than 120 mmol/l) following a period of increased water consumption in 10 psychiatric patients (5 men, 5 women, mean age 48.8 years) treated with neuroleptics and/or benzodiazepines. Other causes of hyponatremia were excluded. The initial clinical signs were associated with severe gastrointestinal and neurological disorders requiring intensive care. In every case a gradual return to normal of natremia was obtained by creating a negative water balance while compensating for the sodium loss. From a study of urine and plasma osmolality ratio (U/P osm) on admission, several physiopathological mechanisms could be envisaged. A U/P osm ratio lower than 1 (6 cases) suggested a water intake exceeding the maximum dilution capacity of the kidneys (20-25 1), or a lesser water intake with little or no osmolal intake, or again an intrarenal disorder of urine dilution. When the U/P osm ratio was higher than 1 (7 cases), reflecting inappropriate secretion of the antidiuretic hormone, the hyponatremia could be explained by the psychosis itself, the treatment taken by the patients, a disorder of thirst regulation and/or a non-osmotic stimulation of vasopressin. This population, therefore, was heterogeneous: the mechanisms which contribute to this pathology are not fully elucidated, and they probably involve several factors.

Adult↗

PubMedDate not supplied

Mechanism of action of endothelins on adrenocortical cells.

Endothelins (ETs) play a pivotal role in the control of various endocrine and neuroendocrine tissues. In this review, we discuss the involvement of ETs as possible regulators of steroid secretion and we describe the mechanism of action of ETs on adrenocortical cells. The occurrence of ETs has been demonstrated in the human, porcine and rat adrenal gland. In humans, immunohistochemical and biochemical techniques have reported that ETs are localized exclusively in the cortex but the presence of ETs has also been detected in pheochromocytomas. In vitro studies have shown that ETs stimulate aldosterone secretion by adrenal tissues in various mammalian and amphibian animal models. The receptor subtype involved in the corticotropic action of ETs clearly differs among the various vertebrate species studied. In rat, the effect of ETs is mediated through an ET(B) receptor subtype while, in frog, an ET(A) receptor is implicated in the stimulatory action of ETs. In human adrenocortical cells, both ET(A) and ET(B) receptor subtypes are involved in the corticotropic effect of ETs. Activation of adrenal receptors causes an elevation of inositol trisphosphates associated with an increase in cytosolic calcium concentration. In addition, ETs induce an elevation of prostaglandin E2 (PGE2) and prostacyclin PGI2 production in the adrenal tissue, indicating that prostanoids may act as second messengers of ETs. It thus appears that ETs present in the adrenal gland may act as paracrine factors to stimulate the secretory activity of adrenocortical cells.

Adrenal Cortex↗

PubMedDate not supplied

[Effect of sustained release alprenolol in hypertension uncontrolled by chlorothiazide and dihydralazine. Study in double blind (author's transl)].

In 20 hypertensive patients with functioning renal graft, sustained release alprenolol or placebo was given orally for 2 months, in combination with chlorothiazide and dihydralazine, after previous failure of these 2 last drugs. Blood pressure was normalized with alprenolol during the length of the study, but is was not with placebo. Mean plasma renine level decreased of 45 p. cent.

Administration, Oral↗

PubMedDate not supplied

[Bronchial tumor and paraneoplastic syndrome of antiduresis: a new case of Schwartz-Bartter's syndrome (author's transl)].

The autors reports about a new case of Schwartz-Bartter's syndrome. Its first clinical manifestations are primarily the neuro-psychiatric disorder and the arterial hypertension. These manifestations were attributed to an inappropriate secretion of antidiuretic hormon, in relation with a bronchial neoplasm (oat-cell carcinoma). The tumor was removed surgically; shortly after the operation the biological disorders disappeared completely. But they reappeared 5 months later, indicating recurrence (local and metastatic). This recurrence started to present clinical manifestation, 2 months later. After a brief historical approach, the authors suggested the aetiology, the diagnosis circumstances and the biological criteria of Schwartz-Bartter's syndrome. Then later, the precised the main principles of its management.

Bronchial Neoplasms↗

PubMedDate not supplied