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

Ultrastructural and cell fractionation studies implicate lipid droplets in the storage of cholesterol and in the secretion of steroids. To evaluate the role of the lipid droplet in steroidogenesis, a discontinuous gradient centrifugation method has been developed for the isolation of both lipid droplet and non-lipid fractions from decapsulated rat adrenal homogenates. Steroids were extracted from the fractions with chloroform/methanol; the cholesterol ester, cholesterol and corticosterone in each extract were purified using a single chromatogram and the purified steroid and sterols were assayed fluorometrically. The lipid droplet fraction contained 85% of the esterified cholesterol and 32% of the free cholesterol found in whole gland extracts. Although adrenal lipid droplet fractions isolated from non-stimulated control animals contained 65-79% of the total corticosterone assayed in extracts of the whole gland, in vivo injections of ACTH did not increase corticosterone in this fraction. On the other hand, the corticosterone measured in non-lipid fraction extracts increased significantly following ACTH treatment. These results suggest that the synthesis/release mechanism for corticosterone is not associated with the lipid droplets but may involve specific components in the non-lipid fraction. The function of lipid droplet corticosterone is unknown.
Steroids 1981 Aug
PMID:A method for the isolation of lipid droplet fractions from decapsulated rat adrenals. 627 53

Bromocriptine treatment in rats (3 mg/kg per day, 7 days) significantly reduced alpha-msh and aldosterone plasma levels 2 hrs after the final treatment in animals on low, normal and high sodium diets. Alpha-MSH dose response curves for corticosterone and 18-hydroxydeoxycorticosterone (18-OH-DOC) in subsequently incubated glomerulosa cells gave stimulation at lower concentrations of alpha-MSH (10(-10) moles per litre) than in cells from untreated animals (10(-9) moles per 1). Curves for aldosterone (ald) and 18-hydroxycorticosterone (18-OH-B) were also affected in cells from animals on a low sodium diet. Fasciculata-reticularis cell responses to ACTH were unaffected. Metoclopramide (4 mg/kg per day, 7 days) elevated plasma alpha-MSH, although ald was unaffected, but inhibited the glomerulosa cell response to alpha-MSH in vitro. Acute dopaminergic responses in plasma ald may be mediated through alpha-MSH in rats, but chronically alpha-MSH may down- regulate glomerulosa cell alpha-MSH receptors. It is unlikely that alpha-MSH mediates the adrenocortical response to sodium depletion.
Steroids 1982 Feb
PMID:Dopaminergic control of aldosterone: modulation of the response of rat adrenal zona glomerulosa cells to alpha-Msh by pretreatment with bromocriptine or metoclopramide. 628 Mar 45

The diurnal variations of the plasma concentrations of eleven steroid hormones and of corticotropin (ACTH) were studied in ten young healthy males. The plasma steroids progesterone, pregnenolone, deoxycorticosterone, 17-OH-progesterone, 17-OH-pregnenolone, deoxycortisol, 18-OH-deoxycorticosterone, corticosterone, aldosterone, cortisol and 18-OH-corticosterone, as well as plasma ACTH, were measured at 30-min intervals in the morning and in the evening and at 2-h intervals during the rest of the day. Steroids were extracted from 1 ml plasma, fractionated by high-pressure liquid chromatography (HPLC) and finally quantified by radioimmunoassay (RIA). Plasma concentrations of ACTH were radioimmunoassayed after extraction from 2 ml plasma. More or less pronounced circadian and episodic variations were apparent for plasma levels of all steroids studied, as well as of ACTH. According to related profiles of diurnal variations of plasma concentrations, three different categories of steroids were tentatively crystallized. Category 1 includes 17-OH-pregnenolone, deoxycortisol, corticosterone, 18-OH-deoxycorticosterone, deoxycorticosterone, cortisol and 18-OH-corticosterone, exhibiting a rhythm partly synchronous with that of the pituitary secretory activity of ACTH. Category 2, including progesterone, pregnenolone and 17-OH-progesterone, exhibited a time course of plasma concentrations assuming a regulation predominantly dictated by the testicular secretory activity. Lastly, aldosterone exerted a variation of plasma concentrations which was obviously regulated by the renin-angiotensin system under the present conditions.
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PMID:Diurnal and ultradian variations of plasma concentrations of eleven adrenal steroid hormones in human males. 628 2

Rats were maintained under standardized conditions of food and water ad libitum and a lighting schedule of 12 h light/we h dark for seven days. Animals were sacrificed at 0500 and 1700 h and tissues were removed and washed. Isolated intact adrenal and pituitary cells were prepared by collagenase treatment. Using a sequential incubation procedure, the release of pituitary ACTH by hypothalamic acid extracts (CRF) was assayed by stimulation of corticosteroid secretion from isolated adrenal cells. Maximum stimulation of adrenal steroids was achieved with hypothalamic extracts and pituitary cells from rats sacrificed at 1700 h, and minimum values were obtained at 0500 h. Intermediate levels were obtained when hypothalamic extracts at one time point were incubated with pituitary cells at the other. The results substantiate the late afternoon peak level of hypothalamic and pituitary secretion occurring prior to the peak activity pattern of the rat.
Steroids 1982 Nov
PMID:Hypothalamic and pituitary periodicity demonstrated by isolated rat adrenal cells. 631 42

The long-term effects of dibutyryl cyclic AMP [(Bu)2-cAMP] on steroidogenesis in bovine adrenocortical cells maintained in primary culture were investigated. During the first 36 h, total steroid production by cells incubated with (Bu)2-cAMP increased progressively. Thereafter, however, there was a marked fall in steroid output. During the first 36 h adrenocortical cells incubated in the presence of (Bu)2-cAMP produced substantially more C19-steroids and 17 alpha-hydroxylated C21-steroids than did cells incubated in the absence of (Bu)2-cAMP. By 48 h, however, such steroid secretion by cells incubated in the continued presence of (Bu)2-cAMP declined toward control levels. By contrast, the secretion of corticosterone and 11-deoxycorticosterone was consistently less by cells maintained in the presence of (Bu)2-cAMP than by cells maintained in its absence. These results suggest that refractoriness results, at least in part, from events which occur distal to the formation of cAMP. The action of ACTH and (Bu)2cAMP to promote the secretion of 17 alpha-hydroxylated C21-steroids and C19-steroids, on the other hand, appears to reflect an increase in the rate of cholesterol side-chain cleavage, as well as an increase in 17 alpha-hydroxylase and possibly also 17, 20-lyase activities.
Steroids 1983 Feb
PMID:Steroidogenic refractoriness of bovine adrenocortical cells to dibutyryl cyclic AMP. 631 99

In the present investigation we evaluated the effect of prostaglandins on the rate of steroid secretion by human fetal adrenal (HFA) tissue. Prostaglandins F2 alpha and E2 (10 micrograms/ml) were added to the culture medium in the presence or absence of ACTH (1 micrograms/ml). The medium was assayed for content of cortisol (F), dehydroepiandrosterone sulfate (DS) and pregnenolone sulfate (PS) by radioimmunoassay. When HFA tissue fragments were maintained in the absence of ACTH, F secretion was low; PGF2 alpha but not PGE2 suppressed F secretion by 60-65%. When ACTH was added to the culture medium, the secretion rate of F increased 15-fold, whereas DS and PS secretion was maintained at or near initial rates of secretion. The addition of PGF2 alpha to the culture medium containing ACTH resulted in a 80% decrease in F secretion, but PGE2 only suppressed F secretion by 50%. In contrast, PGE2 or PGF2 alpha had little effect on the rate of DS or PS secretion either in the presence or absence of ACTH. In conclusion, prostaglandins appear to inhibit the secretion of F, but not of DS or PS by the HFA.
Steroids 1983 May
PMID:Effect of prostaglandins on steroid secretion by human fetal adrenal tissue. 631 2

The molecular and species specificity of glucocorticoid suppression of corticosteroidogenesis was investigated in isolated adrenocortical cells. Trypsin-isolated cells from male rat, domestic fowl and bovine adrenal glands were incubated with or without steroidogenic agents and with or without steroids. Glucocorticoids were measured by radioimmunoassay or fluorometric assay after 1-2 h incubation. Glucocorticoids suppressed ACTH-induced steroidogenesis of isolated rat cells with the following relative potencies: corticosterone greater than cortisol = cortisone greater than dexamethasone. The mineralocorticoid, aldosterone did not affect steroidogenesis. Suppression by glucocorticoids was acute (within 1-2 h), and varied directly with the glucocorticoid concentration. Testosterone also suppressed ACTH-induced steroidogenesis. Glucocorticoid-type steroids have equivalent suppressive potencies, thus suggesting that these steroids may induce suppression at least partly by a common mechanism. Although corticosterone caused the greatest suppression, testosterone was more potent. The steroid specificity of suppression of cyclic AMP (cAMP)-induced and ACTH-induced steroidogenesis were similar, suggesting that suppression is not solely the result of interference with ACTH receptor function or the induction of adenylate cyclase activity. Exogenous glucocorticoids also suppressed ACTH-induced steroidogenesis of cells isolated from domestic fowl and beef adrenal glands, thus suggesting that this observed suppression may be a general mechanism of adrenocortical cell autoregulation.
Steroids 1983 Jun
PMID:Steroid control of steroidogenesis in isolated adrenocortical cells: molecular and species specificity. 632 May 2

Pure hydroxysteroid sulfotransferase (EC 2.8.2.2) of human adrenal glands possesses a wide substrate specificity towards steroids. This wide specificity has now been found to extend to simple alcohols; normal aliphatic alcohols from C3 onwards acting as substrates with C9 showing the highest rate. Increased rate was accompanied by a decrease in Km. In marked contrast to the sulfurylation of steroids such as dehydroepiandrosterone, which exhibit wave-like kinetics, the kinetics with simple alcohols were of the normal Michaelis-Menten type. By means of enzyme antibody and enzyme stability studies evidence was provided that one and the same enzyme was responsible for sulfurylation of hydroxyls on the 3- and 17- positions of steroids and simple alcohols. The data lend support to previous evidence that the enzyme controls the secretion of dehydroepiandrosterone sulfate via steroid-specific binding sites, enabling self-regulation in response to ACTH action.
Steroids 1983 May
PMID:Enzymic synthesis of steroid sulfates XVI. Specificity and regulation of human adrenal hydroxysteroid sulfotransferase. 658 19

Urinary steroidal profiles were studied in five women with Cushing's syndrome and in two normal women that were chosen as controls, by means of gas chromatography and gas chromatography-mass spectrometry. Four patients presented ACTH-dependent adrenal hyperplasia and the last patient had an adrenocortical carcinoma. Steroids were analyzed in urinary extracts, as their respective trimethylsilyloximes and/or trimethylsilylderivatives. Qualitative and quantitative data about 36 urinary steroids were obtained. Three pituitary patients showed a well defined picture of "5-ene pathway" in adrenal function. The fourth patient depicted some primary deficiencies of corticosteroid biosynthesis that overshadowed most biochemical expressions of Cushing's disease. The patient with adrenal carcinoma developed a steroidal pattern resembling autonomous functioning of adrenal cortex inner zones, showing both "5-ene pathway" and "4-ene pathway" increase. This patient also had an unexpected excretion of a major metabolite of 18-hydroxycorticosterone, that did not correlate with parameters of aldosterone production. Tetrahydro-6-hydroxy-cortisol was determined in urine of two patients and original data about urinary cortoic acids in Cushing's syndrome are given. Peripheral reductive metabolism played the most important role in almost all patients. In turn, some oxidative metabolic pathways for cortisol were not specifically favoured in the cases of Cushing's disease here reported.
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PMID:Analysis of urinary steroid profiles of women with Cushing's syndrome by computerised gas chromatography-mass spectrometry. 667 7

The concentrations of aldosterone in the plasma and adrenal glands, the concentrations of sodium and potassium in the plasma and the hematocrit were estimated from birth to day 6 after birth in premature mice removed by Caesarean section on day 19 of pregnancy in comparison with newborn mice delivered spontaneously vaginally on day 20 of pregnancy. In premature mice, the plasma aldosterone concentrations increased twice: at birth after reanimation, then at 6 h after birth. The first increase at birth resulted probably from ACTH stimulation. Several factors could be involved in the peak at 6 h after birth: ACTH stimulation, the decrease in the level of sodium in the plasma and the increase in the hematocrit due to kidney immaturity of premature mice. The results suggest that the renin-angiotensin-aldosterone system is able to respond to stimulations in the first 6 h after birth in premature mice. The rise in the level of plasma aldosterone which has been found at birth in newborns delivered spontaneously vaginally on day 20 of pregnancy (control animals) did not result from variations of plasma electrolytes, plasma volume and ACTH; this rise has been induced by labor of the parturition which caused the aldosterone release from adrenal glands.
Steroids 1982 Sep
PMID:Plasma and adrenal aldosterone levels in premature mice at birth and during neonatal development. 718 5


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