Acta endocrinologica
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Acta endocrinologica · May 1987
Comparative StudyUterotonic activity and myometrial receptor affinity of 1-deamino-1-carba-2-tyrosine(O-methyl)-oxytocin.
The contractile effect of the analogue 1-deamino-1-carba-2-tyrosine(O-methyl)-oxytocin (carbetocin) on isolated myometrial strips from rats was compared with that of oxytocin. The uterotonic activity of the analogue was 15 +/- 3 IU/mg as compared with 438 +/- 41 for oxytocin, however, the response was more prolonged and could not be abolished by washing of the preparation. Despite the low biological activity of carbetocin, its binding affinity to receptors of isolated myometrial plasma membranes was of the same order of magnitude as that of oxytocin. On the basis of the present results it is concluded that a longer half-life of the analogue at the receptor compartment may be a contributing factor to the prolonged uterotonic effect observed in vivo.
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Acta endocrinologica · Oct 1985
The effect of naloxone on ATCH and beta-endorphin in patients with Cushing's disease.
Endogenous opiates may be important in the control of ACTH secretion in men. The effect of opiate receptor blockade by naloxone on ACTH, beta-endorphin-like substance and cortisol release was studied in healthy women and in 9 patients with Cushing's disease. ⋯ However, in 3 our of the 9 patients with Cushing's disease, a paradoxical decrease in serum ACTH, cortisol and beta-endorphin concentrations was observed after naloxone administration. In the patients with a paradoxical response to naloxone, transsphenoidal microadenomectomy was ineffective.
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Acta endocrinologica · Dec 1978
Primary aldosteronism: inability to differentiate unilateral from bilateral adrenal lesions by various routine clinical and laboratory data and by peripheral plasma aldosterone.
In 31 patients with primary aldosteronism routine clinical and laboratory data, the effect of orthostasis on plasma aldosterone (PA), plasma renin activity (PRA) and cortisol (PC), effect of fludrocortisone or high sodium intake on basal PA and night-day fluctuations of basal PA and PC with and without suppression of pituitary ACTH by dexamethasone were determined to differentiate patients with a unilateral aldosterone producing tumour (adenoma, APA, n=20; carcinoma, CA, n=1) from those with idiopathic bilateral adrenal hyperplasia (IAH, n=10). Mean systolic and diastolic blood pressure, age, serum potassium and urinary excretion of sodium and potassium were not significantly different in both groups of patients. Normokalaemic primary aldosteronism occurred both in patients with APA (n=2) and in patients with IAH (n=1). ⋯ A dissociation of PA and PC, however, was only observed in patients with IAH. Finally, the effect of dexamethasone on plasma aldosterone curves was variable in both groups of patients. Our results indicate that under the described conditions analysis of routine clinical and laboratory data and of peripheral PA, PRA and PC are of limited value in differentiating patients with APA or CA from those with IAH.
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Acta endocrinologica · Jun 1977
Increased serum prolactin in diabetic ketoacidosis; correlation between serum sodium and serum prolacting concentration.
In 8 patients with diabetic ketoacidosis, serum prolactin was measured and found to be elevated (24.8 +/- 10.2 ng/ml, mean +/- SEM). After correction of the ketoacidosis, the prolactin level decreased to 10.9 +/- 6.4 ng/ml (normal range men 4.9 +/-0.8, women 5.1 +/- 1.6 ng/ml). The scatter of prolactin values was wide. ⋯ Serum prolactin values did not correlate well with the serum bicarbonate concentration or serum osmolality. However, a significant negative correlation between log serum prolactin concentration and serum sodium concentration was demonstrated (r = -0.61, P less than 0.01). It is suggested that serum prolactin may possible participate in sodium retention in man as has been demonstrated in studies on animals.