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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adrenals obtained from human abortices at midpregnancy were kept under conditions of tissue culture and the production of cortisol and dehydroepiandrosterone sulfate (3beta-hydroxy-5-androsten-17-one, 3-sulfate; DHA-S) monitored by radioimmunoassays for up to 2 weeks. Basal production of dehydroepiandrosterone sulfate was considerably higher than that of cortisol. alpha1-24corticotrophin, alpha1-39corticotrophin, (a long acting porcine corticotrophin) at the concentration of 1 mU/ml of culture medium in both instances, and dibutyryl cyclic AMP (1mM) enhanced the production of both steroids some 3 to 30 times above control values. Medium harvested from homologous pituitary cultures had comparable corticotrophic activity. It is concluded that at midpregnancy the regulation of corticoidogenesis implies the existence of a corticotrophic factor either identical or closely related to ACTH.
Steroids 1977 Mar
PMID:Exploration of the human fetal pituitary adrenal axis: stimulation of cortisol and dehydroepiandrosterone sulfate biosynthesis by homologous pituitary in organ culture. 14 Apr 79

Studies were conducted to further examine the mechanisms responsible for gonadal hormone effects on the rat adrenocortical 11beta-hydroxylase system. Despite higher concentrations of cytochrome P-450 and larger 11-deoxycorticosterone (DOC)-induced difference spectra in adrenal mitochondria from females than males, no sex difference in 11beta-hydroxylase activity was observed. The pregnenolone-induced difference spectrum, indicative of cholesterol binding to cytochrome P-450, also was similar in males and females. Testosterone administration to castrated males lowered both 11beta-hydroxylase activity and mitochondrial cytochrome P-450 content. Estradiol produced the opposite effects in castrated females. However, when given to ACTH-replaced hypophysectomized rats, neither testosterone nor estradiol affected cytochrome P-450 levels or the rate of 11beta-hydroxylation. These observations, taken with the known effects of estradiol and testosterone on ACTH secretion in rats and the effects of ACTH on 11beta-hydroxylation, indicate that gonadal hormone effects on the 11beta-hydroxylase system are mediated by ACTH.
Steroids 1975 Jun
PMID:Relation of the pituitary gland to gonadal hormone effects on the adrenocortical 11beta-hydroxylase system in rats. 16 71

The involvement of cyclic AMP in corticosteroidogenesis was investigated by using isolated adrenal cell column perfusion. Steroids were produced in response to 0.5, 1.0 and 5.0 mg of cyclic AMP/ml. Analysis of the shape of the response curves indicated an inverse relationship between rate of onset of steroid production and dose. A further increase in steroid production during the washout period after the 5 mg/ml dose was considered to indicate an intracellular inhibitory effect of cyclic AMP. Release of cyclic AMP into the perfusate only occurred in response to supramaximal steroidogenic doses of ACTH (adrenocorticotrophin). A connexion between dose and response was demonstrated over a narrow concentration range. Variation in the time-lag before cyclic AMP production and in the duration of the response was marked; further, no reproducible ratio of steroid output to cyclic AMP output was shown at any level of stimulation. These results are discussed together with those of other recent investigations. It is considered that these findings do not support an obligatory role for cyclic AMP as mediator of ACTH action in the adrenal.
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PMID:An investigation of the involvement of adenosine 3':5'-cyclic monophosphate in steroidogenesis by using isolated adrenal cell column perfusion. 17 85

Experiments in vitro on tissue from a feminizing adrenocortical carcinoma removed from a postmenopausal patient are described. Portions of the adrenal tumor were cultured. The effects of ACTH, prolactin, and other protein hormones on the synthesis and secretion of steroid hormones by the cultured tissue were studied. Steroids were extracted from the culture medium with ethyl acetate. Steroid production was determined by high resolution-mass fragmentography and by radioimmunoassay. Results suggest that in vitro neither growth hormone (GH) nor luteinizing hormone (LH), at the concentrations used, effectively stimulated the synthesis and secretion of estradiol-17beta by the adrenal tumor tissue. However, ACTH and prolactin with insulin, appearing to influence the action of both these hormones, stimulated the output of estradiol-17beta. Steroid was being synthesized during the 3-day culture period. The tumor tissue actively synthesized and secreted into the medium estrone as well as estradiol-17beta under the influence of ACTH and prolactin with insulin. Data also suggest that LH and GH were capable of influencing the synthesis and secretion of androstenedione by the tissue explants. No DNA sulphate was present in the media from the tumor tissue cultures before or after incubation with either ACTH or prolactin. Results from studies with normal adrenal tissue in culture indicated that DNA sulphate, DHA, and androstenedione were present in the culture medium after 3 days' incubation. In this report the concentration of endogenous estrone relative to estradiol-17beta and estradiol was found to be high. The effect of protein hormones, other than ACTH, on adenylate cyclase activity of this tumor tissue indicated a lack of specificity of the membrane receptor sites. High resolution-mass fragmentography had greater specificity than radioimmunoassay.
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PMID:In vitro synthesis of steroids by a feminising adrenocortical carcinoma: effect of prolactin and other protein hormones. 18 Jul 40

Studies were designed to determine a) if adrenal glands of hamsters secrete progesterone (PROG), b) the effects of adrenocritocotropin (ACTH) administration on adrenocortial function of rats and hamsters under the surgical conditions necessary for collection of adrenal venous blood from the left renal vein, and c) the effects of blood loss during sample collection. PROG was quantitated by the competitive protein-binding method after extraction and separation by sephadex LH-20 column chromatography. The presence of interfering quantities of androstenedione necessitated two column chromatographic steps. Glucocorticoids (11-OHCS) were determined fluorometrically. PROG was detected in adrenal venous plasma of female hamsters. The PROG concentration and secretory rate were 91 +/- 12 ng/ml and 4 +/- 1 ng/min, respectively, while the peripheral plasma level of the same animals was 2 +/- 0.2 ng/ml, indicating that the adrenal glands of female hamsters are capable of secreting PROG. ACTH administration increased PROG secretory rates in both hamsters (3 +/- 1 to 14 +/- 3 ng/min) and rats (62 +/- 9 to 152 +/- 32 ng/min) on estrus, as well as increasing the 11-OHCS secretory rate of hamsters (16 +/- 1 to 33 +/- 4 ng/min), but not of rats. The greater increase in PRCC than in 11-OHCS secretion may be related to excess PROG formation relative to the capacity of the 17alpha- or 21-hydroxylating enzyme systems. The adrenal venous PROG concentration and secretory rate of female hamsters infused with 10% dextran while collecting adrenal venous blood did not differ significantly from those of the non-infused animals, suggesting that this amount of blood loss (1 ml) does not influence PROG secretion.
Steroids 1976 Aug
PMID:Progesterone secretion by adrenal glands of hamsters and comparison of ACTH influence in rats and hamsters. 18 64

A radioimmunoassay for corticosterone was developed using an antibody to corticosterone-21-hemisuccinate:bovine serum albumin. The assay possessed good specificity, sensitivity and reproducibility and required minimal sample preparation. Tests of adrenal function showed that stimulation of the adrenal with exogenous ACTH and with dexamethasone caused an increase and decrease, respectively, in plasma concentrations of corticosterone. Exposure to cold environmental temperatures caused an increase in plasma corticosterone. Handling and the removal of blood samples by venepuncture had no effect upon the concentration of corticosterone. It was concluded that this assay would accurately measure the response to stresses which affect the pituitary-adrenal axis.
Steroids 1976 Dec
PMID:A radioimmunoassay for corticosterone and its application to the measurement of stress in poultry. 18 65

Neuropeptides related to ACTH, MSH and LPH are involved in acquisition and maintenance of conditioned behaviour. These peptides affect the behaviour by a temporary selective increase in the state of arousal in limbic midbrain structures, thereby increasing the motivational influence of environmental stimuli. Steroids of adrenal origin affect conditioned behaviour in a way opposite to that of ACTH and related peptides. Such steroids alter the arousal level in limbic midbrain structures to enhance discrimination and consequently the elimination of non relevant behaviourla responses. Neuropeptides related to ACTH play a basic role in motivational, learning and memory processes, while the pituitary-adrenal system through the secretion of corticosteroids has a secondary modulationg function.
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PMID:Pituitary adrenal system hormones and behaviour. 19 63

Explants prepared from the neocortex and the fetal zone of the human fetal adrenal (gestational age 13 to 18weeks) were maintained under conditions of organ culture for 7 to 9 days during which time they were exposed to hACTH and various related peptides. Corticotrophic activity was monitored by the daily release of dehydroepiandrosterone sulfate (3beta-hydroxy-5-androsten-17-one, 3-sulfate; DHA-S) and cortisol as quantified by radioimmunoassay, hACTH (2.2 x 10(-9) - 2.2 x 10(-8)M) was the most active in sustaining steroidogenesis by both neocortical and fetocortical cells. alpha-MSH possessed similar properties but not at concentrations lower than 10(-6)M, whereas CLIP (4.4 x 10(-9) - 1.1 x 10(-7)M), the 18-39 C-terminal moiety of ACTH, was devoid of activity. Corticotrophic activity with respect to fetocortical explants appeared to be that of maintenance of function best illustrated by dehydroepiandrosterone sulfate biosynthesis, while enhancement of steroidogenesis was observed in the neocortex as manifested by cortisol release. Although not eliminating the possible existence of a specific fetal corticotrophin related to ACTH1-39, the data indicate that hACTH is capable of regulating steroidogenesis in the fetal zone which is primarily geared to the formation of dehydroepiandrosterone sulfate.
Steroids 1978 Apr
PMID:Steroidogenic activity of hACTH and related peptides on the human neocortex and fetal adrenal cortex in organ culture. 20

A new method for the assessment of endogenous formation of aldosterone in anephric patients is described. (1, 2-3H) aldosterone was administered i.v. to patients 1-2 days before hemodialysis, and then the specific activity (SA) of tetrahydroaldosterone glucosiduronate, the major aldosterone metabolite, was measured in the dialysate using a specific radioimmunoassay. The aldosterone secretion rate was determined from the extent of isotope dilution by endogenous metabolite. Aldosterone secretion rates measured in 10 patients were for the most part low. The secretion rate determined in blood from the aldosterone metabolic clearance rate and plasma aldosterone concentration closely approximate secretion rate values obtained by the isotope dilution method in 3 of 4 patients. In 2 patients in whom ACTH was administered chronically, radio-labeled aldosterone was administered at the start of the study and then the day to day aldosterone secretory response to ACTH was determined from the SA of tetrahydroaldosterone in blood. Aldosterone secretion continuously increased for as long as ACTH was administered.
Steroids 1978 Nov
PMID:A new approach to the difficult assessment of aldosterone secretion in anephric patients. 21 4

Monolayer cultures of mouse adrenal tumor cell line Y-1 have been used to investigate the effects of glucocorticoid on cell replication, [3H]thymidine incorporation into the trichloroacetic acid-precipitated cell fraction, steroidogenesis, and the ACTH receptors of adrenocortical cells. Corticosterone at a concentration of 5.0--50 micrograms/ml inhibited cell replication and [3H]thymidine incorporation into trichloroacetic acid-precipitated cell fraction in a dose-related manner. Corticosterone at a concentration of 0.5--50 micrograms/ml inhibited ACTH-induced steroidogenesis in a dose-related manner. Steroids which do not possess glucocorticoid action did not show such inhibitory effects on cell replication and steroidogenesis of Y-1 cells. The characteristics of the ACTH receptors of these cells remained unaffected by corticosterone. Our findings suggest that synthesized or secreted glucocorticoid may play an important role in the direct regulation of proliferation and function of adrenocortical cells under physiological conditions.
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PMID:Inhibitory effects of corticosterone on cell proliferation and steroidogenesis in the mouse adrenal tumor cell line Y-1. 22 Nov 80


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