Результаты поиска

The Effects of Fungicides on Human 3β-Hydroxysteroid Dehydrogenase 1 and Aromatase in Human Placental Cell Line JEG-3.

Placenta secretes a large amount of progesterone and estradiol, which are critical for maintaining pregnancy. In human placenta, 3β-hydroxysteroid dehydrogenase 1 (HSD3B1) catalyzes pregnenolone to form progesterone, and aromatase (CYP19A1) catalyzes testosterone into estradiol. Fungicides display antifungal activities and are widely used to prevent fungal infections in agricultural plants. These chemicals include azoles, such as tebuconazole (TEB), triadimefon (TRI), and vinclozolin (VCZ) or organotins, such as tributyltin (TBT) and tetrabutyltin (TTBT). Fungicides may disrupt the activities …

The effect of Sutherlandia frutescens on steroidogenesis: confirming indigenous wisdom.

Sutherlandia frutescens (Cancer bush), a Southern African indigenous plant, is traditionally used to treat stress related maladies linked to … by 38% and cytochrome P450 11beta-hydroxylase (CYP11B1) by 60%. The conversion of progesterone and pregnenolone was inhibited by 34% and 30%, respectively. Subsequent extractions with chloroform and methanol showed inhibition of substrate binding and conversion with hydrophobic compounds exhibiting a greater inhibitory effect on deoxycorticosterone binding to …

[Congenital adrenal hyperplasia due to 3beta-hydroxysteroid dehydrogenase deficiency].

Deficiency of 3beta-hydroxysteroid dehydrogenase belongs to less frequent types of congenital adrenal hyperplasia. It is a deficiency of the enzyme converting pregnenolon to progesteron, 17-OH-pregnenolon to 17-OH-progesteron and dehydroepiandrosteron to androstendion in the adrenal glands and gonads. Exact prevalence of forms with clinical symptoms is known; however, it is less frequent compared to deficiency of 21-hydroxylase. Clinical manifestation is very variable, from serious salt disorder, ambiguous genitalia and precocious puberty to oligosymptomatic forms with late effects or asymptom

Mechanisms subserving calcium's modulation of luteinizing hormone action in isolated swine granulosa cells.

We studied the mechanism(s) by which calcium ions modulate progesterone biosynthesis by isolated swine granulosa cells incubated in chemically defined medium in vitro. In selectively calcium-deficient incubations, the capacity of 8-bromo-cAMP to stimulate pregnenolone synthesis from endogenous sterol substrate was significantly impeded. This effect of calcium ions was specific, because calcium ions did not influence basal pregnenolone production or alter progesterone production in response to exogenously supplied cholesterol substrate. Moreover, calcium ions did not modify other biosynthetic p…

Cholesterol side-chain cleavage enzyme activity and cytochrome P-450 content in adrenal mitochondria of a patient with congenital lipoid adrenal hyperplasia (Prader disease).

An autopsied case with congenital lipoid adrenal hyperplasia (Prader disease) was presented. The cholesterol side-chain cleavage (SCC) enzyme activity in adrenal mitochondria of this case was assayed with [3H]cholesterol as substrate, combined with purified bovine adrenodoxin and adrenodoxin reductase, by measuring the amount of [3H]pregnenolone formed. The cytochrome P-450 content was also measured by recording the difference absorption spectra of carbon monoxide-complexed P-450. The cholesterol SCC enzyme activity in adrenal mitochondria of Prader disease was 0.81 nmol pregnenolone/nmol P-45…

Reevaluation of the effects of cytochalasins on steroidogenesis: studies on hamster granulosa cells.

Cytochalasin B (CB), a drug that inhibits microfilament polymerization, as well as having other actions, such as inhibition of hexose transp … ons of cytochalasins, the metabolism of other steroid intermediates was examined: the conversion of pregnenolone to progesterone and the conversion of androstenedione to estradiol. Also, the oxidation of [14C]octanoate to 14CO2, a process that occurs in the mitochondria, was examined. Both CB and CD (1-10 micrograms/ml) inhibited LH- and 8-bromo-cAMP-stimulate …

Стероидомические изменения в цереброспинальной жидкости женщин с множественным склерозом.

Множественный склероз (MS) — долгосрочная болезнь, которая вызывает воспаление и повреждение нервной системы. В ходе этого исследования была проведена оценка стерейдомичных изменений, связанных с НР, у 57 женщин, страдающих НР на фолликулярной фазе, и 17 - на лютнической фазе, а также в области контроля за возрастом и фазой. Данные свидетельствуют о том, что 1) неочищенные и спаренные стероиды тесно связаны между кровью и ССБ. 2) У пациентов с синдромом MS более низкие уровни неочищенных стероидов по сравнению с контрольными. Однако неизменными уровнями содержания спаренных стероидов является

Совпадение в аннотации оригинала
Multiple sclerosis (MS) is a long-term disease that causes inflammation and damage to the nervous system. This study evaluated steroidomic a … s. However, direct measurements of enzyme activity are needed to confirm this hypothesis. (6) Lower pregnenolone levels in MS patients might weaken neuroprotection, while higher pregnenolone sulfate levels could support cognitive function. (7) Lower levels of protective pregnenolone, DHEA, and androstenediol were associated with worse MS, suggesting these ster …

Inhibition of steroid sulphatase activity by steroidal methylthiophosphonates: potential therapeutic agents in breast cancer.

The hydrolysis of steroid sulphates, by steroid sulphatase, is an important source of oestrogenic steroids (oestrone, oestradiol and 5-androstene-3 beta,17 beta-diol) which are found in tumours. In the present study, we have examined the effect of dehydroepiandrosterone-3-O-methylthiophosphonate (DHA-3-MTP), pregnenolone-3-O-methylthiophosphonate (pregnenolone-3-MTP) and cholesterol-3-O-methylthiophosphonate (cholesterol-3-MTP) on the inhibition of oestrone sulphatase as well as DHA sulphatase activities in intact MCF-7 breast cancer cells and in placental microsomes. All three methylthiophosp…

A case of 16-ene-synthetase deficiency in male pseudohermaphroditism due to combined 17 alpha-hydroxylase/17,20-lyase deficiency.

A 17-year-old phenotypic female with primary hypergonadotropic amenorrhea, absence of secondary sexual development, hypertension and 46 XY karyotype is presented. Hormonal analysis revealed very low levels of testosterone, dehydroepiandrosterone, androstenedione, estrogens, cortisol and high levels of ACTH, progesterone, deoxycorticosterone and corticosterone. Enzyme studies of the testicular tissue after bilateral gonadectomy showed absence of 17 alpha-hydroxylase and 17,20-lyase activity as well as 16-ene-synthetase activity. This enzyme catalyzes the reaction from pregnenolone to 5,16-andro…

Enhancement of Muscimol Binding and Gating by Allosteric Modulators of the GABAA Receptor: Relating Occupancy to State Functions.

Muscimol is a psychoactive isoxazole derived from the mushroom Amanita muscaria and a potent orthosteric agonist of the GABAA receptor. The … l predicts enhancement of [3H]muscimol binding in the presence of the steroids allopregnanolone and pregnenolone sulfate, although the steroids interact with distinct sites and either enhance (allopregnanolone) or reduce (pregnenolone sulfate) receptor function. We infer that the concerted transition model can be used to link radioligand binding and electrophy …

Abnormal plasma neuroactive progestagen derivatives in ill, neonatal foals presented to the neonatal intensive care unit.

REASONS FOR PERFORMING THE STUDY: Increased levels of pregnanes have been reported in foals with neonatal maladjustment syndrome (NMS). Thes … of life (P<0.01). Foals with NMS and sick, non-NMS foals had significantly increased progesterone, pregnenolone, androstenedione, dehydroepiandrosterone and epitestosterone concentrations compared with healthy foals (P<0.05). Progesterone and pregnenolone concentrations of sick, non-NMS foals decreased significantly over 48 h (P<0.05), whereas concentrations …

GABAergic neuroactive steroids: a new frontier in bipolar disorders?

Neurosteroids are synthesized in the brain and modulate brain excitability. There is increasing evidence of their sedative, anesthetic and antiseizure properties, as well as their influence on mood. Currently neurosteroids are classified as pregnane neurosteroids (allopregnanolone and allotetrahydrodeoxycorticosterone), androstane neurosteroids (androstanediol and etiocholanone) or sulfated neurosteroids (pregnenolone sulfate and dehydroepiandrosterone sulfate). Both preclinical and clinical findings indicate that progesterone derivative neurosteroids such as allopregnanolone and allotetrahydr…

The human kidney is a progesterone-metabolizing and androgen-producing organ.

Progesterone (P) is a potent antagonist of the human mineralocorticoid receptor (MR) in vitro. We have previously demonstrated effective dow … e/17,20-lyase (P450c17). The presence of 3 beta-HSD type 2 and P450c17 indicated that conversion of pregnenolone to dehydroepiandrosterone (DHEA) and to androstenedione may take place effectively in kidney. To investigate this further, we incubated kidney subcellular fractions with radiolabeled pregnenolone. This resulted in efficient formation of DHEA from pr …

Effect of 4-hydroxyandrostenedione on murine Leydig tumor cell steroidogenesis.

The murine Leydig cell tumor (M5480A) possesses high levels of estrogen receptor and is known to produce estrogens. In these studies we exam … lowing 1 h of incubation, but this effect disappeared coincident with 4-OHA metabolism. Analysis of pregnenolone production revealed a biphasic dose-dependent effect of 4-OHA. At low doses (0.01-0.1 microM), 4-OHA was found to decrease pregnenolone concentrations, while at higher doses (1-10 microM) pregnenolone levels were elevated. Therefore, the actions of …

Isolation of theca cells from human antral follicle membranes using ANPEP-based magnetic cell sorting.

RESEARCH QUESTION: Can ANPEP-based magnetic activated cell sorting (MACS) be used to isolate and functionally enrich human steroidogenic the … Gene expression (ANPEP, CYP17A1, LHCGR, FSHR, CYP19A1) was analyzed by RT-qPCR. Steroid secretion (pregnenolone, progesterone, 17-OH-pregnenolone, 17-OH-progesterone, DHEA, androstenedione) was quantified using LC-MS/MS. RESULTS: Before cell sorting, 29.6-82.9% of viable cells expressed ANPEP. After MACS, ~ 68% of cells in the ANPEP-positive fraction express …

Effects of fluorine substitution on substrate conversion by cytochromes P450 17A1 and 21A2.

Cytochromes P450 17A1 (CYP7A1) and 21A2 (CYP21A2) catalyze key reactions in the production of steroid hormones, including mineralocorticoids, glucocorticoids, and androgens. With the ultimate goal of designing probes that are selectively metabolized to each of these steroid types, fluorinated derivatives of the endogenous substrates, pregnenolone and progesterone, were prepared to study the effects on CYP17A1 and CYP21A2 activity. In the functional assays, the hydroxylase reactions catalysed by each of these enzymes were blocked when fluorine was introduced at the site of metabolism (positions…

Steroidogenesis in amlodipine treated purified Leydig cells.

Drugs have been shown to adversely affect male fertility and recently anti-hypertensive drugs were added to the list. The anti-fertility effects of amlodipine, a calcium channel blocker, are well-illustrated in in vivo experiments but lack an in vitro proof. The present study was designed to experimentally elucidate the effects of amlodipine on Leydig cell steroidogenesis and intracellular calcium in vitro. Leydig cells of Sprague-Dawley rats were isolated and purified by Percoll. Cells were incubated for 3h with/without amlodipine in the presence/absence of LH, dbcAMP, Pregnenolone and 25-Hyd…

Trifluoperazine inhibits progesterone and cyclic AMP production in granulosa cells of the hen (Gallus domesticus).

Unstimulated (basal) as well as luteinizing hormone (LH)-promoted progesterone production in collagenase-dispersed hen granulosa cells was inhibited in a dose-related manner by two phenothiazines, trifluoperazine (TFP) and chlorpromazine (CP), both of which are known calmodulin antagonists. Using TFP, the more potent antagonist of the two, it was found that LH-stimulated cyclic AMP production was also suppressed. Moreover, TFP attenuated the steroidogenic effects of both 8-bromo-cyclic AMP and isobutylmethylxanthine but had no effect on the conversion of pregnenolone to progesterone. The inhib…

Regulation of steroid secretion by adrenal tissue of a human anencephalic fetus.

ACTH-stimulated adrenal tissue of a human anencephalic fetus, when maintained in organ culture, secreted appreciable quantities of cortisol but little dehydroisoandrosterone sulfate or pregnenolone sulfate. In the absence of ACTH, cortisol secretion was severely attenuated. Arginine vasopressin or alpha MSH, when added to the culture medium, did not stimulate steroid secretion. When whole human serum was present in the culture medium bathing the adrenal tissue of the anencephalic fetus, the rate of cortisol secretion was similar to that attained when lipoprotein-poor serum was in the medium. B…

The hypothalamic steroidogenic pathway mediates susceptibility to inflammation-evoked depression in female mice.

BACKGROUND: Depression is two-to-three times more frequent among women. The hypothalamus, a sexually dimorphic area, has been implicated in … s confirmed as a potential sex-specific pathway in the hypothalamus of female mice with depression. Pregnenolone, an upstream component of the steroid hormone biosynthesis pathway, was downregulated in female mice with depressive-like phenotypes but not in males and had considerable relevance to depressive-like behaviors in females. Moreover, exogenous pregnen …