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

Testicular cholesterol side-chain cleavage enzyme (CSCCE) and delta5-3beta-hydroxysteroid dehydrogenase (delta5-3beta-HSD) activities were assessed 12 hours and 2, 4, 8, 16, and 32 days after surgical induction of bilateral cryptorchidism in adult rats. Within 12 hours after surgery CSCCE activity (expressed as dpm of isocaproic acid-14C formed from cholesterol-26-14C/3 hours/testis) was significantly reduced (P less than 0.01) in cryptorchid testes to approximately 55% of sham-operated control values and remained depressed at less than 50% of control activities 2, 4, 16, and 32 days after surgery. Cryptorchid testis delta5-3beta-HSD activity (measured by a pregnenolone substrate-depletion assay and expressed as mumoles of products/30 minutes/testis) did not differ from controls (P greater than 0.05) 1/2, 2, or 4 days after translocation of testes to the abdominal cavity. By day 8 of cryptorchidism, however, delta5-3beta-HSD activity was reduced to 60% of control values (P less than 0.05) and continued to decline to approximately 30% of controls during the remainder of the experimental period. These observed alterations in enzyme activities suggest an impairment in the ability of cryptorchid rat testes to synthesize androgens and further indicate that testicular CSCCE is more acutely sensitive to the cryptorchid milieu than delta5-3beta-HSD.
Steroids 1978 Feb
PMID:Influence of experimental cryptorchidism on cholesterol side-chain cleavage enzyme and delta5-3beta-hydroxysteroid dehydrogenase activities in rat testes. 2 94

A 3beta-hydroxysteroid dehydrogenase (3betaHSD) was demonstrated in term human fetal membranes (chorion and amnion) with both dehydroepiandrosterone (3beta-hydroxy-5-androsten-17-one) and pregnenolone (3beta-hydroxy-5-pregnen-20-one as substrates, and the subcellular distribution substrate and nucleotide specificity of the enzyme was studied. In both membranes the microsomal fraction (particles which sedimented at 105,000 g after 90 min) had the highest specific activity. The chorion was more active than the amnion but the enzyme in both tissues had similar substrate and nucleotide specificity. NAD was the preferred cofactor, and pregnenolone was a better substrate than dehydroepiandrosterone in the presence of NAD. However, with NADP as cofactor both steroids were equally good substrates. When the 3beta-hydroxysteroid dehydrogenase activity of chorion microsomes was compared with that of placental microsomes, the specific activities were found to be of the same order of magnitude, and the substrate, nucleotide specificity and steroid binding properties were almost identical.
Steroids 1978 Oct
PMID:3beta-Hydroxysteroid dehydrogenase activity in human fetal membranes. 3 Oct 18

Steroid metabolism in hepatoma tissue culture (HTC) cells derived from a male rat was investigated. Steroids in ethanol were incubated with the cells for various lengths of time. Volume of ethanol never exceeded 1% of incubation volume. Thin-layer and paper chromatography were used. Incubation was with tritiated steroids. It was demonstrated that testosterone as well as dihydrotestosterone is transformed. The main enzyme activities detected were 5alpha-reduction and 3alpha-, 3beta, and 17beta-hydroxysteroid dehydrogenation. The pattern of metabolism was reproducible and varied with time, substrate concentration, and number of cells incubated. Some steroids interfered with androgen metabolism. 17beta-estradiol, 17-epitestosterone, and progesterone competed for the 17beta-hydroxyprogesterone dehydrogenase. it is concluded that 3beta and 17beta reduction in the HTC cells may be catalyzed by the same enzyme which might differ considerably from the 3beta-hydroxysteroid dehydrogenase assayed in intact liver cells. A hepatoma derived from a female rat also produced considerable amounts of 3beta-derivatives of testosterone.
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PMID:Metabolism of testosterone and dihydrotestosterone in cultured rat hepatoma cells. 17 19

The 3beta-hydroxysteroid dehydrogenase activity in whole bovine ovaries was systematically studied using dehydroepiandrosterone (3beta-hydroxy-5-androsten-17-one) and pregnenolone (3 beta-hydroxy-5-pregnen-20-one) as substrates, in order to determine whether, in this tissue, the same or different 3beta-hydroxysteroid dehydrogenases metabolize these steroids. The majority of the activity, with both substrates was found in the microsomes. Detergent extraction of the microsomes indicated that more than one enzyme was present in this fraction. A number of experiments on the Triton X-100 extract of the microsomes (the stability of the activity, its nucleotide specificity and kinetic analyses) were most simply explained by a single enzyme metabolizing both steroids. However, the stereospecificity of hydride-ion transfer from pregnenolone to NAD+ (B transfer) was different than that from dehydroepiandrosterone to NAD+ (A and B transfer). Thus, as no single enzyme is known to catalyze the transfer of hydride-ion to both sides of NAD+, it is proposed that there are at least two 3beta-hydroxysteroid dehydrogenases in the Triton X-100 extract.
Steroids 1976 Jul
PMID:The specificity of the 3beta-hydroxysteroid dehydrogenase activity of bovine ovaries toward dehydroepiandrosterone and pregnenolone: evidence for multiple enzymes. 18 14

A cloned cell line of human choriocarcinoma was evaluated as a model of human placental oestrogen production. Oestrone formation from dehydroepiandrosterone (D), D-sulphate (DS) or 4-androstenedione (A) was less than or equal to 5% of oestradiol-17beta (Oe2) formation. Oe2 formation from D and A was similar (100-150 pmole/h/10(7) cells); that from DS was 10 times less. Omitting serum from the medium increased Oe2 yield from DS 4-fold; addition of albumin restored these yields to control values (P greater than 0.05, t-test), presumably by binding DS. N6,O2'-dibutyryl-adenosine 3',5'-cyclic monophosphoric acid and theophylline treatment for 72 h stimulated (P less than 0.01) Oe2 formation from D (36%), DS (66%) and A (183%). In intact cells, sulphatase activity, Oe2 formation from D and Oe2 formation from DS equalled those in homogenates (P greater than 0.05) but Oe2 formation from D was greater than that from DS in both systems (P less than 0.001), indicating a deficiency of sulphatase relative to subsequent enzymes of oestrogen synthesis. Steroids, at concentrations previously shown to inhibit placental sulphatase or 3beta-hydroxysteroid dehydrogenase, did not inhibit choriocarcinoma enzymes. Except for its relative sulphatase deficiency and insusceptibility of oestrogen synthesizing enzymes to steroid inhibitors, choriocarcinoma appears to be a useful model of placental oestrogen synthesis.
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PMID:Oestrogen formation from C19 precursors in human choriocarcinoma in culture. 19 Aug 43

A simple procedure is described for solubilizing microsomal 3beta-hydroxysteroid dehydrogenase (3beta-HSD). Microsomes from rat adrenals or from testicular interstitial cells were incubated for 1 or 2 h at 0 C in a buffer containing NaCl followed by overnight storage at -20 C. Maximum solubilization of 3beta-hydroxy-5beta-androstan-17-one-HSD (androstane-3beta-HSD) was obtained by incubating adrenal microsomes with 1 M NaCl and interstitial cell microsomes with 2 M NaCl. Incubation with NaCl for 1 or 2 h resulted in maximum solubilization; incubation with NaCl for 4, 8 or 24 h did not change the amount of enzyme solubilized. From adrenal microsomes incubated with 1 M NaCl, up to 80% (105.7 millimicron/mg microsomes) of the total androstane-3beta-HSD activity was recovered in the supernatant following centrifugation at 130,000 x g for 1 h. The maximum amount of androstane-3beta-HSD solubilized from interstitial cell microsomes was 56% (29.5 millimicron/mg microsomes) at 2 M NaCl. The "solubilized" androstane-3beta-HSD was retarded when chromatographed on a Sephadex G-200 column and it did not pellet out when centrifuged at 130,000 x g for 15 h. KCL appeared to be equally effective in solubilizing androstane-3beta-HSD from microsomes. Other steroid dehydrogenase activities such as pregnanolone-HSD and 3beta-hydroxy-5alpha-androstan-17-one-HSD were also found in the 130,000 x g supernatant.
Steroids 1977 Nov
PMID:A simple procedure for solubilizing 3beta-hydroxysteroid dehydrogenase from microsomes of rat adrenals and testis interstitial cells. 61 35

Trilostane is a competitive inhibitor of 3beta-hydroxysteroid dehydrogenase. In vitro, the drug inhibits conversion of pregnenolone to progesterone but does not alter conversion of cholesterol to pregnenolone nor progesterone to corticoid hormones. When given orally to rats, trilostane inhibits corticosterone and aldosterone production and elevates circulating levels of pregnenolone at doses lower than those that produce adrenal hypertrophy or inhibit gonadal steroidogenesis.
Steroids 1978 Sep
PMID:Trilostane, an orally active inhibitor of steroid biosynthesis. 71 20

Steroids which are synthesized within the nervous system, such as progesterone, have been termed 'neurosteroids'. Levels of progesterone are much larger in peripheral nerves of rats and mice than in plasma, and persist after removal of the steroidogenic endocrine glands. Schwann cells are a source of progesterone: when isolated from embryonic dorsal root ganglia, they can synthesize progesterone from pregnenolone, the obligate precursor of all steroids. Locally produced progesterone has been shown to play an important role in myelination of peripheral nerve. We show here that sensory neurons from embryonic dorsal root ganglia also express 3beta-hydroxysteroid dehydrogenase and can convert [3H]pregnenolone to [3H]progesterone. Moreover, when cultured under different conditions and incubated for 24 h in the presence of 100 nM [3H]pregnenolone, they produce 5-10 times more [3H]progesterone than Schwann cells. The conversion of pregnenolone to progesterone by neurons is further increased by a diffusible factor produced by Schwann cells. Sensory neurons can also metabolize progesterone to 5alpha-dihydroprogesterone, but unlike Schwann cells, they do not produce 3alpha,5alpha-tetrahydroprogesterone, a potent positive allosteric modulator of gamma-aminobutyric acid type A receptors. We also show that cells isolated from the adult nervous system still have the capacity to convert [3H]pregnenolone to progesterone and its 5alpha-reduced metabolites: neurons and Schwann cells purified from dorsal root ganglia of 6 week old male rats show a similar pattern of pregnenolone metabolism to cells isolated from 18 day old embryos. These findings further support the important role of progesterone in the development and regeneration of the peripheral nervous system.
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PMID:Neurosteroids: expression of functional 3beta-hydroxysteroid dehydrogenase by rat sensory neurons and Schwann cells. 946 19

Principal cells show marked structural differences in the proximal, middle, and distal regions of the vas deferens, reflective of diverse functional activities. In the present study, we performed electron microscopy to examine the structural features of principal cells using glutaraldehyde-fixed, Epon-embedded material, while functional parameters were examined using light microscopic immunocytochemistry on Bouin-fixed, paraffin-embedded material. In the proximal region, the cuboidal principal cells resembled those of the cauda epididymidis, but few clear cells and occasional narrow cells were present. In the middle region, principal cells often contained blebs of their apical cytoplasm containing vesicular and tubular profiles. These blebs extended far from the cell surface and appeared to be liberated into the lumen, suggesting an apocrine type of secretion. In the distal region, dilated intercellular spaces containing numerous membranous profiles of different shapes and sizes were noted between adjacent principal cells and overlying basal cells. The use of an anti-aquaporin-1 antibody revealed an intense reaction over the endothelial cells of numerous vascular channels in the lamina propria. Taken together, these observations suggested water transport from the lumen of the vas deferens via the dilated spaces to underlying vascular channels, the function of which may be to concentrate sperm. The infranuclear cytoplasm of principal cells of this region showed whorls of smooth endoplasmic reticulum (sER). Large intracytoplasmic cavities were found within the sER aggregates, and these contained membranous profiles that appeared to peel off from the surrounding sER elements. Various images of such cavities closely juxtaposed to the lateral plasma membrane suggested that the membranous profiles of the intercellular spaces were derived from them. Use of anti-3beta-hydroxysteroid dehydrogenase antibody revealed an intense reaction over principal cells of the vas deferens, as well as over the blebs in the lumen of the vas deferens, which is indicative of the steroid synthesis performed by these cells. The release of sER membranous profiles into the dilated spaces and the presence of blebs in the lumen may represent a means of transporting steroids that are destined for different sites out of the principal cells. Steroids in the blebs would be ultimately destined for utilization by luminal sperm, while those steroids in the dilated spaces are designed for utilization by muscle layers of the lamina propria. In summary, principal cells of the vas deferens appear to be involved in synthesis and secretion of steroids and in eliminating water from the lumen of the vas deferens.
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PMID:Principal cells of the vas deferens are involved in water transport and steroid synthesis in the adult rat. 1010 Apr 86

A novel compound, NO-1886, which possesses a powerful lipoprotein lipase activity-increasing action, induces hypertrophy of adrenals in rats and hyperplasia of cortical cells in dogs. However, these effects were not observed in monkeys. We examined the effects of NO- 1886 on steroid hormone production by adrenocortical cells to clarify its effects on adrenal steroidogenesis. NO-1886 did not inhibit the steroid synthetic enzymes, including 3beta-hydroxysteroid dehydrogenase, 21-hydroxylase, 11beta-hydroxylase, or cholesterol side-chain cleavage enzymes. However, NO-1886 affected steroid production from adrenocortical cells in rats, dogs, monkeys, and humans in in vitro studies. These effects were almost completely reversed by the addition of 25-hydroxycholesterol or low-density lipoproteins to the reaction medium, but not reversed by the addition of high-density lipoproteins. These results suggest that NO-1886 affects the cholesterol pathways within the adrenocortical cells and inhibits steroidogenesis, causing a reduction of steroid hormone release from adrenocortical cells and resulting in hypertrophy of adrenals via feed-back mechanisms. However, its effect is not apparent in animals that use low-density lipoproteins as a source of adrenocortical steroidogenesis.
Steroids 1999 Jul
PMID:Lipoprotein lipase promoting agent, NO-1886, modulates adrenal functions: species difference in effects of NO-1886 on steroidogenesis. 1044 1


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