Etude biochimique de la sécrétion physiologique et du métabolisme de la 11bêta-hydroxyandrosténédione chez l'homme

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

INFLUENCE OF PHENOBARBITAL ON HORMONE RELEASE AFTER INSULIN-INDUCED HYPOGLYCEMIA

SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe

Serial measurements of vitamin B 12 and vitamin B 12 binding capacity in marasmic kwashiorkor

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Simultaneous radio-immunoassay measurement of testosterone (T) and dihydrotestosterone (DHT) without chromatography

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Influence of phenobarbital on hormone release after insulin induced hypoglycemia

SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe

Detection of heterozygote carriers of congenital adrenal hyperplasia

Heterozygote carriers of 21-hydroxylase deficiency (21-OHD) cannot be detected by measurements of basal adrenal secretion. Attempts were made to reveal the latent metabolic block by ACTH stimulation and determination of plasma 17-hydroxyprogesterone (17-OHP). Overlapping of the response curves between normals and carriers prevented their use for individual prediction purposes. The test sensitivity was improved as follows: endogenous ACTH interference was suppressed by dexamethasone prior to I.V. injection of ACTH: plasma 17-OHP, cortisol (F), progesterone (P), corticosterone (B) and androstenedione (AD) were measured (during the 1 h duration of the test): parameters analyzed were the ratio of plasma increments between precursors and end-products (Δ17-OHP/ΔF, ΔP/ΔB, Δ17-OHP/ΔAD) at corresponding times: data were analysed by a stepwise discriminant analysis. The test was performed in 22 normal adults and 14 parents of children with 21-OHD. The following results were obtained: significant alterations in the metabolic pathways of F and B but not in the conversion of 17-OHP to AD were demonstrated in carriers; addition of ΔP/ΔB results did not improve the discriminant potency of statistical analysis performed in the Δ17-OHP/ΔF data; within the limits imposed by the number of subjects studied, the discriminant analysis applied to the Δ17-OHP/ΔF data revealed a combination of variables which lead to a 91% correct classification for normals and carriers.SCOPUS: NotDefined.jinfo:eu-repo/semantics/publishe

Preparative HPLC for analysis of mineralocorticoids in human plasma

A method has been developed to measure simultaneously in human plasma the mineralocorticoids and glucocorticoids involved in mineralocorticoid excess. Briefly: plasma extracts were chromatographied in a fully-automated procedure on a lichrospher-diol column using a hexane: isoproanol: trithylamine gradient. Eluates were collected on a preprogrammed fraction collector. Final quantification was achieved by RIA on the selected fractions. This procedure allowed: 1) the separation of each measured steroid from plasma contaminants; 2) precise collection; 3) quantification of mineralocorticoids with a precision and sensitivity equivalent to that of direct methods; and 4) improved specificity. © 1987 Friedr. Vieweg & Sohn Verlagsgesellschaft mbH.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Specific determination of plasma dexamethasone by HPLC and RIA--application to standard dexamethasone suppression test in psychiatric patients.

Three radioimmunoassays (RIA), with or without preparative HPLC, were applied to the monitoring of plasma dexamethasone (DXM) levels during standard dexamethasone suppression test (DST) in psychiatric patients. Due to the robotic ease of the fully automated HPLC process, precision of the chromatographic assay was equivalent to that of the direct assays, but prepurification improved both sensitivity and specificity. These improvements allowed the elucidation of the following features: (1) half (36) of the patients (68) displayed infranormal DXM levels (less than or equal to 0.40 ng/ml) whatever the cortisol response; (2) 22% (15) patients (68) with DXM levels in the low control range showed a strong inhibition of cortisol suppression. These observations raise some doubts on the validity of the DST test and introduce the following questions. (1) What is the dependence of cortisol suppression upon DXM absorption and catabolism? (2) Does plasma DXM measurement several hours after its physiological action still reflect its effect on the hypothalamo-hypophyseal axis? (3) What is the reliability of DXM direct assays when measuring low DXM levels in the presence of high cortisol?Journal Articleinfo:eu-repo/semantics/publishe

Evolution of the Δ4-adrenal androgens responsiveness in childhood during insulin test

Serum 11-β-hydroxy-androstenedione (11OHAD), androstenedione (AD) and cortisol (F) were estimated during an i.v. insulin test in 2 large groups of normal prepubertal children and in normal adults. The results revealed that the basal level and responsiveness of AD were much lower in both groups of children than in adults whereas the corresponding 11OHAD data were similar or superior to those of adults. This suggests that during childhood the limited amount of adrenal AD is preferentially switched to the 11-hydroxylation step. Comparison of hormonal data observed in adults after i.v. insulin (mild ACTH stimulation) and a maximal stimulating dose of synacthen showed that the sensitivity of Δ4-3 keto-androgens pathway is inferior to that of F.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Kinetics of plasma corticosteroids during metyrapone infusion in man

The effect of metyrapone on plasma kinetics of cortisol (F), 11-deoxycortisol (S), corticosterone (B), 11-deoxycorticosterone (DOC), aldosterone (Aldo) and 17 hydroxyprogesterone (17 OHP) was studied in ten normal prepubertal children intravenously infused with the drug (1 gm/1.73 m2 body surface area in 4 h). Similar falls in F, B and Aldo were observed during the first hour expressing similar sensitivity of the 11 hydroxylases to the drug. The effect of the compensatory increase of endogenous ACTH could be detected after 1 hour by the rise in 17 OHP. However the concentrations of the 11-hydroxy compounds, F, B and Aldo, remained low throughout the infusion period. From the second hour onwards, facilitation of the synthesis of DOC was noticed. After the end of infusion, the levels of the precursors decreased and F and B were restored to initial values. Also remained low probably due to the inhibitory effect of the elevated DOC on the renin-angiotensin system.SCOPUS: ar.jFLWNAinfo:eu-repo/semantics/publishe