Search PubMed⌕ Search

Biomedical subjects

M Ben-David

Publications and source records attributed to M Ben-David.

At least 55 records · Page 3Linked to original sources
PubMed1978

Prolactin secretion during and after Noveril infusions to depressive patients.

Dibenzapine (720 mg, Noveril) was infused intravenously to 16 depressed patients during a period of 3 h. Serum prolactin levels were determined by radioimmunoassay and changes in clinical condition were evaluated according to the Hamilton Equation. The two variables were correlated to each other. In most of the patients Noveril caused a dramatic but short-lived improvement in depressive symptoms. There was much variability in the prolactin response to the drug. Serum prolactin levels showed a great elevation in 9 patients. In all patients the hormonal levels returned to their former normal levels after termination of the infusions. The treatment was then continued with Noveril per os. There was no significant correlation between serum prolactin levels and clinical condition or its change. The elevation of serum prolactin levels as a reaction to Noveril treatment may be explained by the prominent serotonergic action of Noveril. A time lag between serotonergic and dopaminergic actions of the drug when given in higher doses may be an additional explanation. Other possible hypotheses are discussed.

Clinical Trials as Topic↗
PubMed1978

Prolactin suppression by (-) delta-9-tetrahydrocannabinol (THC): involvement of serotonergic and dopaminergic pathways.

(-) delta-9-Tetrahydrocannabinol (THC) was previously shown to suppress serum PRL levels (SPL) in rats. In the present study, various pathways by which THC suppresses PRL secretion were investigated. THC abolished the elevated SPL induced by either 5-hydroxytryptophan or melatonin. The SPL suppression after THC treatment was abolished upon treatment with cyproheptadine. These results suggest on involvement of a serotonergic pathway in the suppressive effect of THC on PRL secretion. Elevated SPL induced by a low dose of the dopaminergic blocker pimozide was suppressed after treatment with THC. However, elevated SPL, induced by a high dose of pimozide or by any dose of perphenazine (a less specific dopaminergic blocker), were not reduced by combined treatment of either of these drugs with THC. It seems that THC also enhances the dopaminergic activity in the pathway that controls PRL secretion. In addition, the pimozide-induced SPL elevation dropped upon combined treatment of cyproheptadine and pimozide. As cyproheptadine alone, and in the dose used, did not affect SPL, it is proposed that the serotonergic and dopaminergic pathways that control PRL secretion do not necessarily act independently of one another.

Animals↗
PubMed1978

Prolactin in seminal plasma of infertile men.

Twenty-one fertile and 103 infertile patients with oligospermia, azoospermia, impaired sperm motility and hypogonadism were evaluated for prolactin concentrations in serum, seminal plasma and split seminal plasma of two fractions. Prolactin concentration in the seminal plasma was two to three times higher than serum prolactin levels in fertile and infertile men. Prolactin concentration of the fraction 2 of the split ejaculate was higher than that of the fraction 1 and of the serum. Excessive high levels of serum prolactin and/or seminal plasma were found only among infertile patients with oligo- and azoospermia, impaired motility and hypogonadotropic hypogonadism. Prolactin is selectively accumulated in fraction 2 of the split ejaculate and affects the constituents of the seminal vesicular fluid, and excessive high prolactin concentrations of either seminal plasma or serum may be associated with male infertility.

Humans↗
PubMed1978

Failure of bromocriptine to suppress prolactin in majeptil-induced hyperprolactinemia.

A case of hyperprolactinemic anovulation with amenorrhea and galactorrhea, due to Phenothizine derivative (Majeptil) is presented. Treatment with bromocriptine, 2.5 mg b.i.d., p.o., or L-Dopa, 500 mg, p.o., did not suppress serum prolactin and menstrual cycle was not resumed. Pituitary prolactin response to TRH and Pituitary LH and FSH response to LHRH were found to be normal. It seems that at the dose used, bromocriptine (a dopaminergic agonist) cannot counteract the phenothiazine induced hyperprolactinemia. Hence, it is not effective in induction of ovulation while the patient is under phenothiazine treatment.

Adult↗
PubMed1977

Preparation of bio- and immunoactive human prolactin in milligram amounts from amniotic fluid in 60% yield.

Bio- and immunoactive human prolactin (hPRL) was isolated from amniotic fluid. The overall yield is a single passage through the procedure was 60%; 5 liters of amniotic fluid (10 mg hPRL) yielded 3 mg (30%) of a mixture of hPRL isohormones A, B (both minor), C and D (both major), and less than 10% contamination with extraneous protein. A further 3 mg hPRL was less highly purified. Two mg hPRL was recycled. The product has been stable for at least 1 year at--70 C, suitable for iodination, and gave rise to RIA dose-response curves indistinguishable from those obtained with pituitary hPRL. The isolated hormone, after stoichiometric iodination, is active in binding to both mammary gland and liver cell membrane receptors and exhibits a biological activity, in the local pigeon crop-sac assay, of 47.3 +/- 6.1 IU/mg. The isolation procedure consisted of 3 steps: 1) hollow-fiber dialysis to concentrate amniotic fluid; 2) gel filtration on Sephadex G-50 to remove bulk contaminants; 3)isoelectric focusing in a density gradient, taking advantage of the elevated isoelectric points, relative to contaminants, of hPRL isohormones (6.0-6.5, corrected). Production of this preparation, carried out on two separate occasions, required each time 3 months of a single investigator's time, inclusive of assay work.

Amniotic Fluid↗
PubMed1977

Serum prolactin in normal and pathologic pregnancy.

Serum prolactin values in normal pregnant women showed a progressive increase from a mean value of 50 ng/ml in the 12th week to 270 ng/ml at term, with the range at term being 100-600 ng/ml. There was a fairly good correlation (r = 0.7) between the values of 24-hour urine estriol in 138 determinations and in the serum prolactin in 133 pregnant women. The regression lines of serum hPRL values with time of gestation in cases of intrauterine growth retardation (IUGR) and diabetes mellitus were less steep than those seen in normal pregnancy. The serum hPRL value of patients with preeclamptic toxemia, latent diabetes, premature rupture of membranes, or multiple pregnancies were found not to differ significantly from the values observed in normal pregnancy. The results indicate that prolactin determinations in pathologic pregnancies are not useful as an aid in their evaluation.

Estriol↗
PubMed1976

Serum-prolatic in women with premenstrual syndrome.

Serum-prolactin was measured by radioimmunoassay during the menstrual cycle in 28 women who had the premenstrual syndrome (P.M.S.) and in a control group who did not have P.M.S. symptoms. Throughout the menstrual cycle mean serum-prolactin was signficantly higher in women with P.M.S. than in the controls. The average individual increase in serum-prolactin during the premenstrual period compared with the first 3 weeks of the cycle was also significantly higher in women with P.M.S. It is not clear whether the increase in serum-prolactin was merely an indicator of stress or was actually involved in producing some of the symptoms which constitute P.M.S.

Adult↗
PubMed1976

Hyperprolactinemic male infertility.

Serum prolactin was studied in 25 fertile and 127 infertile men. The latter included 91 oligospermic, 27 azoospermic, and 9 hypogonadotropic hypogonadal men. The mean prolactin level in all three groups of infertile men was significantly above that of the fertile group. There was no correlation among serum levels of follicle-stimulating hormone, luteinizing hormone, sperm count, and serum prolactin values. Hyperprolactinemia was found in five patients (two oligospermic, one azoospermic, and two hypogonadotropic hypogonadal men). Bromocriptine, 2.5 mg twice daily, suppressed hyperprolactinemia. In one man with hyperprolactinemic oligospermia, treatment with bromocriptine yielded significant improvement in sperm count (to normal values).

Adult↗
PubMed1976

Osmotic control of prolactin release and its effect on renal water excretion in man.

Prolactin appears to play a role in osmoregulation of fishes and birds and a possible contribution of this hormone to the regulation of salt and water excretion in mammals has been suggested as well. The present studies were undertaken to investigate the role of osmotic pressure on the secretion of prolactin and the effect of the hormone on renal water excretion in man. The i.v. administration of synthetic thyrotropin releasing hormone (TRH) (7 mug/kg) to five subjects undergoing a maximal sustained water diuresis increased serum prolactin to supraphysiologic levels in all as mean concentration rose from 30.2 +/- 2.9 to 60.2 +/- 5.0 ng/ml (P less than 0.005). This increase was not associated with either significant alterations in renal hemodynamics or sodium excretion and water excretion. The osmoregulation of prolactin release was then investigated by the oral administration of 20 ml/kg of water to seven subjects in 11 studies. While the water load decreased serum osmolality from 293 +/- 285 +/- 1.5 mOsm/kg H2O (P less than 0.001), there was no significant change in prolactin level, 28+/- 1.8 to 30 +/- 2.4 ng/ml. Serum hypertonicity was achieved in six subjects with the infusion of 5% NaCl which increased serum osmolality from 287 +/- 1.8 to 298 +/- 1.4 mOsm/kg (P less than 0.001). While the hypertonic state caused a marked antidiuresis as urinary osmolality rose from 62 +/- 5.9 to 480 +/- 48 mOsm/kg (P less than 0.001), the concentration of prolactin remained unchanged at 28 ng/ml. We conclude that supraphysiologic levels of prolactin have no antidiuretic properties in a vasopressin-free state and that acute alterations in serum tonicity within the range observed do not affect the release of prolactin in man.

Adolescent↗
PubMed1976

Serum prolactin and the suppression of lactation.

Bromocriptine (2 bromo-alpha-ergocryptine), stilboestrol, clomiphene citrate, testosterone propionate and a placebo were given to 75 postpartum women for the suppression of puerperal lactation. An additional 15 women who breast-fed their babies served as a control group. Blood samples were taken for the determination of serum prolactin levels by a specific homologous double antibody radioimmunoassay. Concurrently, the clinical effectiveness of the various treatments was assessed. High levels of prolactin were found at the time of delivery. Bromocriptine effectively reduced serum prolactin and prevented lactation; stilboestrol increased serum prolactin and partially suppressed lactation; clomiphene citrate and testosterone propionate both lowered serum prolactin levels and partially suppressed lactation. The placebo showed almost no effect on serum prolactin. It appeared that bromocriptine was the drug of choice in the suppression of puerperal lactation.

Bromocriptine↗
PubMed1975

Prolactin in normal pregnancy: relationship of maternal, fetal, and amniotic fluid levels.

Serum prolactin was measured simultaneously by a homologous radioimmunoassay in 92 parturients and their offspring at term, and in maternal serum and amniotic fluid during various stages of normal pregnancy. Serum levels of 208 +/- 8 ng. per millilter were found in maternal blood; the corresponding levels in the cord serum were 354 +/- 14 ng. per milliliter. Prolactin levels in amniotic fluid were found to be 2- to 10-fold higher than the corresponding levels of the mothers. The possible source of the amniotic fluid prolactin molecule, which is identical with the human pituitary molecule, is discussed.

Amniotic Fluid↗