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At least 127 records · Page 7Linked to original sources
PubMed1982

Partial characterization of unusual polar steroids in the urine of a child with low renin hypertension.

Analysis of urinary steroids excreted by a 7-year old girl with low renin hypertension following ACTH treatment revealed several unknown steroids, which have been analysed by gas chromatography-mass spectrometry. It is proposed that these steroids are monohydroxylated derivatives of cortisol, cortisone, either or both tetrahydro and allo-tetrahydrocortisol and either or both tetrahydro and allo-tetrahydro-11-deoxycortisol. Further analysis indicated that there are two likely positions for the additional hydroxyl group, either on the A or B ring.

Adrenocorticotropic Hormone↗
PubMed1982

Interactions of antiglucocorticoids with glucocorticoid receptors.

Six known or potential antiglucocorticoids were used as steroid probes in a competitive binding assay to elucidate the binding specificity of the agonist sites of four different rat glucocorticoid receptors. The object was to determine whether the binding of this class of steroids was particularly sensitive to subtle differences between these sites. Cytosolic extracts of heart, pancreas, kidney and liver were evaluated. The order of competitive potency for the first three preparations was found to be medroxyprogesterone greater than deoxycorticosterone greater than progesterone greater than R-5020 greater than cortexolone greater than 17-hydroxyprogesterone. The order for the glucocorticoid receptor of liver, on the other hand, was R-5020 greater than progesterone greater than deoxycorticosterone greater than medroxyprogesterone greater than cortexolone greater than 17-hydroxyprogesterone. Although this partial reversal of specificity could reflect a difference in the agonist site of the liver receptor, mixing experiments, in which cytosolic extracts of liver were incubated with kidney cytosol extracts, demonstrated that the liver cytosol contained an additional factor that could change the apparent specificity of the kidney glucocorticoid receptor. This factor was stable at 0 degrees C for at least 18 h, heat-labile and non-dialyzable. These results suggest that the liver receptor's specificity may actually be the same as the other three, but appears to be different in this type of assay because of this additional factor. It is similar that their agonist sites are most likely identical.

Animals↗
PubMed1983

The stimulatory effect of corticotropin on cortisol biosynthetic pathway in guinea-pig adrenocortical cells.

The mechanism of the prolonged stimulatory effect of corticotropin (ACTH) on adrenocortical synthesis of cortisol was studied in guinea-pig adrenocortical cells harvested from control animals and from guinea-pigs submitted 24 h before the sacrifice to a prolonged ether anesthesia in an attempt to induce a release of endogenous ACTH. As a result of this in vivo exposure to endogenous ACTH, the maximal capacity to produce glucocorticoids (by 1 X 10(5) cells incubated during 2 h) in response to ACTH increased from 579 +/- 111 ng (control group) to 915 +/- 143 ng for cells from treated animals, whereas the apparent affinity of the steroidogenic response to ACTH remained unchanged. This hyper-reactivity of cells from anesthetized animals was also evident in the presence of dibutyryl cyclic AMP. Moreover, there was increased conversion of exogenous pregnenolone into cortisol by cells from previously anesthetized animals. It was therefore concluded that ACTH increases in a lasting way the activity of steroidogenic pathway leading to cortisol synthesis by adrenocortical cells at sites distal to cyclic AMP generation. Besides an obvious increase of formation of pregnenolone in response to ACTH, it seems that this ACTH-induced enhancement in the capacity of the steroidogenic response to ACTH also implies a prolonged stimulatory influence of the peptide on the post-pregnenolone steroidogenic pathway leading to cortisol synthesis.

Adrenal Cortex↗
PubMed1984

Inhibition of cortisol production in isolated guinea-pig adrenal cells.

Cortisol, added to 1 ml incubation medium containing 3-4 X 10(5) isolated guinea-pig adrenal cells, provoked a decrease in basal and ACTH (250 pg)-stimulated cortisol production, in correlation with the amounts used (50 ng-2,000 ng). A decrease in aldosterone production could be seen when cortisol concentrations reached or exceeded 1,000 ng/ml. There were no variations in either androgens (delta 4-androstenedione, dehydropiandrosterone) or 17-hydroxyprogesterone. Only 11-deoxycortisol was slightly increased. Using increasing concentrations of ACTH (50-250 pg), both in the absence and in the presence of 1,000 ng cortisol, it was noted that the inhibition induced by cortisol was of a competitive type and could be overcome by ACTH. This decrease in cortisol was concomitant with an increase in 11-deoxycortisol. Neither corticosterone nor dexamethasone reduced cortisol production. In addition, it was shown that the conversion of tritiated 11-deoxycortisol to radioactive cortisol increased significantly under the influence of 250 pg ACTH (mean relative variation of 21.7% +/- 7.7 (SEM), n = 6, P less than 0.05); but decreased significantly under the combined effect of 1,000 ng exogenous cortisol and the same dose of ACTH: (mean relative variation of 4.3% +/- 1 (SEM), n = 8, P less than 0.005). There is therefore reason to believe that the concentrations of cortisol at the adrenal level modulate the stimulation induced by ACTH and that this self-adjustment forms part of the control mechanisms involved in corticosteroidogenesis.

Adrenal Glands↗
PubMed1984

Effect of antiglucocorticoids on dexamethasone-induced inhibition of uridine incorporation and cell lysis in isolated mouse thymocytes.

We have compared in isolated mouse thymocytes the action of progesterone, cortexolone, DXH (a 17-beta carboxamide derivative of dexamethasone) and RU 38486 (a new antiglucocorticoid molecule), on dexamethasone-induced inhibition of uridine incorporation and cell lysis, with the affinities of these drugs for glucocorticoid receptors. Our results show that progesterone, cortexolone and DXH which possess similar affinities for glucocorticoid receptors may exhibit variable, weak agonist and antagonist activities according to the parameter studied. RU 38486 was a potent competitor of dexamethasone and was able, when present in a 10-fold excess, to counteract almost completely the inhibitory action as well as the lytic action of 5 X 10(-8) M dexamethasone. This compound which exerts almost no agonist activity may therefore represent a useful tool to investigate the mode of action of antiglucocorticoids.

17-Hydroxycorticosteroids↗
PubMed1984

The effect of partially purified dexamethasone receptor on RNA synthesis in rat thymus and liver nuclei.

DEAE Sephadex-A-50 chromatography of rat liver and thymus cytosol charged with dexamethasone (0.1 microM) and heated at 25 degrees C for 30 min, separates two main hormone--receptor complexes, one in the flow through (DE-1) and one eluting with 150 mM [Cl-] (DE-2). Incubation of these two fractions with homologous nuclei results in a 20% stimulation and a 20-25% inhibition of transcription of liver and thymus nuclei, respectively. No difference was observed between the action of DE-1 and DE-2. If the DE-1 and DE-2 fractions of cytosol charged with the glucocorticoid antagonist, cortexolone, are used under the same experimental conditions, no effect on the transcriptional activity of liver or thymus nuclei can be observed. The fact that from nuclei only DE-1 can be isolated, not DE-2, suggests that DE-1 is the intranuclearly active form and that DE-2, with a still unknown mechanism, is transformed to DE-1. A linear relation exists between the number of GR-complexes (DE-1 or DE-2) translocated and the change in RNA synthesis. Transcriptional effects start when a critical number of acceptor sites are occupied in the nucleus (approximately 200-300 sites/nucleus) for both receptor forms.

Animals↗
PubMed1984

The stimulation by ACTH of 17 alpha-hydroxylation in cultures or rabbit adrenal cells.

Adrenal cells from control rabbits (control-cells) and from rabbits that had been injected twice daily for 3 days prior to sacrifice with 25 IU ACTH (ACTH-cells) were cultured both in the absence and presence of 100 mIU ACTH. Culture durations varied from 24 to 120 h in 24 h increments. The culture medium was changed daily and fresh ACTH added to appropriate vessels. At the time of the final media change 0.1 muCi [4-14C]pregnenolone was added. Twenty-four hours later the cultures were terminated and the products formed from the pregnenolone were isolated, quantified and identified by solvent extraction, chromatography and crystallization to constant specific activity. After 72 h ACTH-cells cultured in the presence of ACTH converted 18.5% of the pregnenolone substrate to 17-hydroxycorticosteroids (cortisol plus 11-deoxycortisol) while ACTH-cells cultured in the absence of ACTH converted a maximum of 1.6%. A similar but smaller difference, 10.9 vs 2.1%, was recorded with control cells cultured in the presence and absence of ACTH. Corticosterone production from [4-14C]pregnenolone in the 72-h cultures was increased to a lesser degree by ACTH exposure. In ACTH-cells the conversion climbed from 5.9 to 10.5% and from 9.6 to 12.0% in control cells. Microscopic examination of parallel cultures showed no significant differences in cell density between cells cultured in the presence or absence of ACTH. 17 alpha-Hydroxylase activity arising from the in vivo stimulation did not survive cell division in culture, but required the continual presence of ACTH. In conclusion, the data show that ACTH is capable of stimulating 17-hydroxycorticoid formation in rabbit adrenal cell cultures.

Adrenal Glands↗
PubMed1984

Development of plasma 21-deoxycortisol radioimmunoassay and application to the diagnosis of patients with 21-hydroxylase deficiency.

Specific 21-deoxycortisol (21-DF) antiserum was raised in New Zealand white rabbits using a 21-DF-3,20-oxime-bovine serum albumin complex. Plasma radioimmunoassay of 21-DF was developed and used together with a radioimmunoassay of 17-hydroxyprogesterone (17-OH-P) for diagnosis of patients with 21-hydroxylase deficiency of congenital and postpubertal forms. The assays were performed in plasma extracts after isolation by paper chromatography. The response of plasma 21-DF and 17-OH-P to i.v. ACTH (25 IU) was studied in 15 adult controls and compared to 8 women with the late onset form of 21-hydroxylase deficiency and 23 women with idiopathic hirsutism. Normal 21-DF values for women were 6.9 +/- 3.6 ng/dl and for men 9.71 +/- 2.73 ng/dl. Newborn children (age: 3-10 days) had a value of 8.3 +/- 4.8 ng/dl. These values are definitely lower than the lowest value ever published. This is possibly due to the specificity of the antibody. During the menstrual cycle the 21-DF values did not change. The baseline and post-stimulated concentrations of hormone were similar in controls and women with hirsutism but were significantly higher in women with the late onset form of 21-hydroxylase deficiency. In the congenital form of 21-hydroxylase deficiency the 21-DF values (baseline) were high. In general, the 21-DF and 17-OH-P values have shown parallel changes. However, one case of 21-hydroxylase deficiency with elevated 21-DF but normal 17-OH-P was observed. The use of 21-DF for the diagnosis of 21-hydroxylase deficiency is suggested.

17-Hydroxycorticosteroids↗