Corticosteroidogenesis by isolated human adrenal cells: Effect of serotonin and serotonin antagonists

Summary The direct effect of serotonin and antiserotonin agents on adrenal steroid biosynthesis was studied in isolated adrenal cells derived from patients with Cushing's syndrome. The results indicate that serotonin increases corticosterone production, while the serotonin antagonists cyproheptadine and methysergide depress adrenal steroid-particularly cortisol and aldosterone-biosynthesis.The authors are indebted to Dr. M. Kárteszi, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, for the determination of plasma ACTH by radioimmunoassay in our patients, and to Prof. P. Vecsei, Department of Pharmacology, University of Heidelberg, providing us with highly specific antisera for corticosteroids RIA-s.     

Negative inotropic effect of some H2-receptor antagonists on the isolated human atria

H2-Receptor antagonists were found to possess in various degrees a negative inotropic effect on human atria in vitro. This effect seemed to be independent of H2-receptor blockade and, at least in the case of oxmetidine, seemed to involve calcium ion transport and/or utilization.     

Inhibition of ovulation in rats by antagonists to serotonin and by a new tricyclic compound.

The ovulation inhibiting activity in adult rats of the 5HT-antagonists cyproheptadine, mianserin and methysergide is shown. Furthermore the activity of a newly synthetized Cycloheptathiophenederivative, compound 26-921, which inhibits LH-secretion and consequently ovulation, is described.     

Inhibition of ovulation in rats by antagonists to serotonin and by a new tricyclic compound

Summary The ovulation inhibiting activity in adult rats of the 5HT-antagonists cyproheptadine, mianserin and methysergide is shown. Furthermore the activity of a newly synthetized Cycloheptathiophenederivative, compound 26–921, which inhibits LH-secretion and consequently ovulation, is described.     

Stimulation by ACTH of protein synthesis in cultured adrenal cells. Absence of an effect by cyclin AMP]

ACTH stimulates the incorporation of 14C-leucine into proteins of adrenal tumor cells in culture. This stimulation though about 20% over controls is statistically significant. Cyclic AMP did not reproduce the stimulation observed with ACTH.     

Opposite effect of PGE2 on cAMP levels in human adrenal medulla and pheochromocytoma.

PGE2 (10(-7) M) caused increased cAMP accumlation in 5 pheochromocytomas, while in 3 human adrenal medullae PGE2 caused a significant decrease of cAMP level on incubating slices in vitro. This finding is discussed in relation to the opposite effect of PGE2 on catecholamine release from human medulla and pheochromocytoma slices in vitro.     

Identification of hemolytic granules isolated from human myocardial cells

Human myocardial cells from fresh autopsy material contained granules which possessed hemolytic activity against guinea pig and rabbit erythrocytes. The hemolytic granules, which had a density of 1.02 and a diameter of 200-300 nm, were recovered as a microsome fraction from subcellular homogenates of human myocardial cells by differential centrifugation in 300 mM sucrose containing 0.1 mM PMSF and 10 mM EDTA. The membrane lesions caused by the granules were ring-like structures with an internal diameter of about 10-17 nm, analogous to that caused by perforin- and complement-induced lysis. However, the requirement for divalent cation differed from that for perforin-induced lysis, since the microsome-mediated lysis occurred in the presence of EDTA.     

Identification of hemolytic granules isolated from human myocardial cells

Summary Human myocardial cells from fresh autopsy material contained granules which possessed hemolytic activity against guinea pig and rabbit erythrocytes. The hemolytic granules, which had a density of 1.02 and a diameter of 200–300 nm, were recovered as a microsome fraction from subcellular homogenates of human myocardial cells by differential centrifugation in 300 mM sucrose containing 0.1 mM PMSF and 10 mM EDTA. The membrane lesions caused by the granules were ring-like structures with an internal diameter of about 10–17 nm, analogous to that caused by perforin- and complement-induced lysis. However, the requirement for divalent cation differed from that for perforin-induced lysis, since the microsome-mediated lysis occurred in the presence of EDTA.     

Opposite effect of PGE2 on cAMP levels in human adrenal medulla and pheochromocytoma

Summary PGE₂ (10^–7 M) caused increased cAMP accumulation in 5 pheochromocytomas, while in 3 human adrenal medullae PGE₂ caused a significant decrease of cAMP level on incubating slices in vitro. This finding is discussed in relation to the opposite effect of PGE₂ on catecholamine release from human medulla and pheochromocytoma slices in vitro.Acknowledgment. This paper is part of a Ph. D. thesis of Punya Boonyaviroj.Established Investigator of the Chief Scientist's Bureau, Israeli Ministry of Health.     

H2 receptor antagonists and human granulopoiesis

The effect of 2 H2 receptor antagonists (ranitidine and cimetidine) on the in vitro growth of human granulomonopoietic precursors (CFU-GM) was studied. Ranitidine, although having an anti H2 receptor activity much greater than that of cimetidine, displays the same toxicity for CFU-GM.     

H2 receptor antagonists and human granulopoiesis

Summary The effect of 2 H₂ receptor antagonists (ranitidine and cimetidine) on the in vitro growth of human granulomonopoietic precursors (CFU-GM) was studied. Ranitidine, although having an anti H₂ receptor activity much greater than that of cimetidine, displays the same toxicity for CFU-GM.Acknowledgments. This work was supported by CNR, Rome, PFCCN and AIRC, Milan.     

The effect of age and pinealectomy on the hypertension produced by adrenal regeneration

Zusammenfassung Nach Pinealektomie unterbleibt eine Hypertonie (Skelton), falls einseitige Nephrektomie und Adrenektomie mit Enukleation der übrigen Nebenniere bei jungen Ratten durchgeführt wurde. Wird die experimentelle, Hypertonie verursachende Operation bei adulten Tieren praktiziert, so bleibt Pinealektomie ohne jeden Effekt.     

The effect of insulin on the glycogen metabolism of isolated fat cells

Résumé (1) Des adipocytes isolés à partir du tissu adipeux épididymaire du rat ont été incubés dans des milieux contenant du glucose (1¹⁴C) et des concentrations variables d'insuline. La quantité de glucose (1¹⁴C) transformée en glycogène (¹⁴C), (¹⁴C)O₂ et triglycerides (¹⁴C) a été déterminée. (2) On démontre que la quantité de glucose (1¹⁴C) transformée en glycogène par des adipocytes peut être évaluée et qu'elle est fonction de la concentration d'insuline. (3) La comparaison entre les effets d'insuline sur les transformations du glucose (1¹⁴C) en glycogène (¹⁴C), en triglycerides (¹⁴C) ou (¹⁴C)O₂ révèle que l'insuline a une action apparemment directe sur l'incorporation du glucose au glycogène. (4) Ce fait serait donc dû à un effet direct de l'insuline sur une réaction dans la synthèse du glycogène par les adipocytes ou à une grande affinité des enzymes participant à la synthèse du glycogène pour le glucose-1-phosphate et à leur faible capacité pour la synthèse du glycogène.