Search PubMed⌕ Search

Biomedical subjects

W E Nicholson

Publications and source records attributed to W E Nicholson.

95 records · Page 6Linked to original sources
PubMed1967

Radioimmunoassay of beta-MSH in human plasma and tissues.

A radioimmunoassay method for beta-melanocyte-stimulating hormone (beta-MSH) has been developed and utilized in the identification and quantification of this hormone in human plasma and tissues. The concentration of beta-MSH in two human pituitary glands was found to be approximately 350 mug/g. beta-MSH was identified in the tumor tissue of all 11 patients with the ectopic ACTH syndrome who were studied; concentrations in individual cases ranged from 3 to 1600 ng/g. In plasma of chronically hyperpigmented patients with Addison's disease, Cushing's disease (after bilateral adrenalectomy), and the ectopic ACTH syndrome, beta-MSH concentrations of 0.5-6 ng/ml were found. The degree of clinical hyperpigmentation was well correlated with the quantity of beta-MSH in the plasma. beta-MSH concentrations in the plasma of normal subjects were less than 0.09 ng/ml. In all of these circumstances, bioassays for MSH were also performed, and it was found that most of the biologic MSH activity of the plasma and tissues could be accounted for by beta-MSH.

Addison Disease↗
PubMedDate not supplied

Angiotensin stimulates cortisol biosynthesis in human adrenal cells in vitro.

Adrenal glands obtained from patients undergoing therapeutic adrenalectomy were used to study the effects of angiotensin on human adrenal steroidogenesis. It was observed that angiotensin stimulated cortisol biosynthesis. Although this has been demonstrated to occur in canine and bovine adrenals, angiotens in-induced cortisol biosynthesis has not been established in man. The possibility that angiotensin merely stimulated glomerulosa cells to secrete precursor steroids which accumulated in the medium and then diffused into fasciculata cells to provide substrate for cortisol biosynthesis was excluded by demonstrating that 3beta-hydroxy-5-pregnen-20-one (pregnenolone) and progesterone (the only pertinent precursors) did not accumulate in angiotensin-stimulated cell suspension. In addition, angiotensin stimulated cortisol biosynthesis in a fasciculata cell suspension in which angiotensin did not stimulate aldosterone production. Therefore, in human adrenal cell suspensions angiotensin appeared to act directly to stimulate cortisol synthesis by fasciculata cells. In normal subjects pre-treated with dexamethasone, angiotensin infusions failed to stimulate an increase in plasma cortisol. The physiological importance of angiotensin as a regulator of cortisol secretion remains, therefore, to be established.

Adrenal Glands↗