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Biomedical subjects

J A Silverman

Publications and source records attributed to J A Silverman.

78 records · Page 5Linked to original sources
PubMed1975

Sex dependence of clearance rates of aldosterone and its metabolites from plasma of intact rats.

Following I.V. injection of 3H-aldosterone, the rates of clearance of plasma 3H-radioactivity was demonstrated to be sex-dependent in intact rats. Even though the percentages of CH2Cl2-extractable plasma radioactivity are greater in female than in male rats, the quantities of CH2Cl2-extractable label are similar until 60 min post-injection. However, the quantities of non-extractable, polar metabolites of aldosterone (NEPD) are markedly greater in the plasma of males and rapidly reach peak levels 10 min post-injection of aldosterone. In females, these polar metabolites (NEPD) are rapidly cleared from the blood. After bile-duct cannulation, the rate of excretion of aldosterone radiometabolites was demonstrated to be rapid and sex-dependent. Within 1 hr., female rats excreted via the bile 82% of the injected dose of 3H-aldosterone, compared to 49% in male rats. In both sexes, greater than 95% of the total radioactivity excreted in the bile are non-extractable polar metabolites of aldosterone (NEPD). The sex hormones appear to influence not only the nature of metabolism of aldosterone in the liver, but also the rates of clearance of aldosterone and its metabolites from the plasma into the bile.

Aldosterone↗
PubMed1975

Biliary excretion of [3H]aldosterone and its sex dependence in adrenalectomized rats.

The rate of excretion of 3-H-radioactivity via the bile into the intestine following intravenous injection of [3-H]aldosterone, was demonstrated to be rapid and sex-dependent in adrenalectomized rats. Within 1 h, female rats excreted into the intesting via the bile greater than 95% of the injected dose of [3-H]aldosterone, compared to 47% in the male rats. In both the male and female rats, greater than 90% of the total radioactivity excreted into the intestine represented dichloromethane nonextractable polar derivatives of aldosterone (NEPD). Similarly, the quantities of NEPD recovered in the bile following bile duct cannulation of the rats, were also sex-dependent. These findings account for the rapidity and sex-dependence of the rates of clearance of aldosterone and its metabolites from the plasma of adrenalectomized rats. The sex hormones appear to influence not only the extent and the routes of metabolism of aldosterone in the liver, but also the rates of clearance of aldosterone and its metabolites from the plasma into the bile.

Adrenal Glands↗
PubMed1974

Anorexia nervosa: clinical observations in a successful treatment plan.

This poorly understood disease has been studied in 27 girls and two boys. Metabolic aberrations included electrocardiographic abnormalities, hypovitaminosis A, hypercarotenemia, abnormal oral glucose tolerance curves, decreased xylose excretion, decreased excretion of luteinizing (LH) and follicle-stimulating hormones (FSH), decreased serum thyroxine levels, absence of diurnal variation of plasma concentrations of glucocorticoids, elevation of blood urea nitrogen, bone marrow hypoplasia, and leukopenia. With restoration of proper nutrition, most of these abnormalities (except FSH and LH) were corrected. An effective method for inpatient treatment is described. There were no deaths during this period of study.

Adolescent↗
PubMedDate not supplied

Anorexia nervosa: a cause of pericardial effusion?

Echocardiographic studies revealed the presence of pericardial effusion in 4 patients with anorexia nervosa, whose weights had fallen by 38 to 53% of their body weight at the onset of disease. Each patient had a normal or small cardiac image on chest roentgenogram. The presence of increased pericardial fluid may partially explain the decreased voltage on the electrocardiogram, and the distant heart sounds heard in some of these patients. The cause of the pericardial effusion is not clear. It may possibly occur in other diseases that produce marked weight loss and cachexia.

Adolescent↗
PubMedDate not supplied

Cortical and ventral tegmental systems exert opposing influences on self-stimulation from the prefrontal cortex.

Intracranial self-stimulation (ICSS) was obtained from 3 areas of anteromedial cortex: the prelimbic area (Brodman's area 32), the anterior cingulate area and the posterior cingulate area. Electrical stimulation in the prelimbic and anterior cingulate areas also produces a behavioral inhibition which is most pronounced at anterior sites (i.e. prelimbic) and declines at increasingly more posterior sites. It was found that the acquisition of responding for ICSS and the magnitude of amphetamine's facilitation of ICSS were inversely related to the degree of behavioral inhibition. These data and the ability of amphetamine to reverse prefrontal stimulation-induced inhibition suggest an important interaction between the prefrontal cortex and the mesolimbic dopamine systems in the control of goal-directed behavior. A model involving cortical suppression of mesolimbic dopamine function is discussed.

Animals↗