Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q8NEX9 (reductase)
 26,410 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A body of information now supports the existence of an ovarian intrafollicular insulin-like growth factor (IGF)-I system concerned with the amplification of FSH action at the level of the rat granulosa cell. In this study we examined the ability of IGF-I to modulate the basal and FSH-supported activity and expression of key steroidogenic enzymes concerned with progesterone generation and metabolism in cultured granulosa cells from immature rats. The provision of IGF-I stimulated FSH-supported (20 ng/ml) accumulation of progesterone in a dose-dependent manner, reaching a plateau at an IGF-I dose of 50 ng/ml. This dose of IGF-I substantially enhanced FSH action over a broad range of FSH concentrations, reaching a maximum at an FSH dose of 20 ng/ml. Pulse labeling of FSH-pretreated cells with [3H]pregnenolone revealed relatively rapid (< 5 h) transformation to [3H]progesterone and other distal products that was accelerated by the concurrent addition of IGF-I. These changes in progesterone metabolism were associated with IGF-I-mediated enhancement of the activities and expression of key steroidogenic enzymes. Specifically, treatment with IGF-I produced significant augmentation of the FSH-stimulated activities of cholesterol side-chain cleavage (P450scc) and 3 beta-hydroxysteroid dehydrogenase/ isomerase (3 beta-HSD) enzymes (2.4- and 1.8-fold, respectively). Similarly, P450scc and type I 3 beta-HSD transcripts were elevated by FSH in a dose-dependent manner, the concurrent addition of IGF-I further increasing expression (up to an additional 3-fold) in the range of 1-5 ng/ml (but not at the maximally stimulating dose of 20 ng/ml FSH). The addition of IGF-I also increased basal levels of type I 3 beta-HSD transcripts (3.8-fold). IGF-I enhanced FSH-stimulated 20 alpha-HSD activity and transcripts (2.3-fold and 1.8-fold, respectively) and increased the basal levels of 20 alpha-HSD transcripts (3-fold). Basal levels of 5 alpha-reductase were slightly elevated (1.3-fold) by IGF-I, but the FSH-attenuated activity was unchanged. Taken together, these findings suggest that IGF-I enhances the FSH-supported accumulation of progesterone in cultured granulosa cells through up-regulation of the expression and activity of key enzymes in the steroidogenic pathway. The acceleration of progesterone accumulation reflects a newly established steady state, favoring the activities of progesterone-forming over progesterone-metabolizing enzymes.
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PMID:Insulin-like growth factor-I-mediated amplification of follicle-stimulating hormone-supported progesterone accumulation by cultured rat granulosa cells: enhancement of steroidogenic enzyme activity and expression. 909 77

The ability of the male gonad to convert androgens into estrogens is well known; the microsomal enzymatic complex involved in this transformation is named aromatase and is composed of a specific cytochrome P450 aromatase (P450arom) and a ubiquitous reductase. Using a highly specific RT-PCR method we have measured the amount of P450arom mRNA in purified Leydig and Sertoli cells prepared from 20, 40 and 70-80 day-old rats. The amount of P450arom mRNA in the Leydig cells is independent of age (40 x 10(-3) attomoles/micrograms of total RNA); in contrast, in the immature rat Sertoli cells, after 5 days of culture the amount of P450arom mRNA is 20-fold lower when compared to that of 20-day-old rat Sertoli cells (71 x 10(-3) attomoles/micrograms of total RNA). Nevertheless, irrespective of the age, the addition of either FSH or dbcAMP for 6 h increases the level of P450arom mRNA in the rat Sertoli cell preparations. Therefore, we evidenced that during testicular maturation not only the Leydig cells but also the Sertoli cells of the rat have the capacity to express the gene for cytochrome P450 aromatase.
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PMID:[In vitro gene expression of aromatase in rat testicular cells]. 918 Nov 20

Isotretinoin, used to treat severe acne, has been shown to induce hormonal changes, especially to reduce 5 alpha-reductase in the production of the tissue-derived dihydrotestosterone (DHT) metabolite 3 alpha-Adiol G. However, the effects of isotretinoin on other pituitary, adrenal or gonadal hormones have not been thoroughly elucidated. In the present study, isotretinoin administered at a dose of 0.5 mg/kg/day for 4 weeks caused no marked changes in the serum levels of pituitary, adrenal or gonadal hormones or 3 alpha-Adiol G in patients with severe papulopustulotic acne (n = 19). After 12 weeks of therapy, there was a decrease in the levels of the precursor androgens androstenedione, testosterone and 3 alpha-Adiol G in 6/9 patients. Acne improved after 4.5 months in all but 2 male patients, who had very low serum hormone binding globulins (SHBG) and a high free androgen index (FAI). Isotretinoin did not affect the elevated LH/FSH ratio in a patient with the polycystic ovarian syndrome (PCOS); nor did it change the high FAI or low SHBG in the male patients. For comparison, tetracycline had no effects on the serum hormonal levels of patients with mild acne (n = 19) after 7 days of treatment. This study confirms that the effects of isotretinoin on the serum hormone levels are small and unlikely to be of relevance for the resolution of acne or the suppression of sebum excretion.
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PMID:Isotretinoin, tetracycline and circulating hormones in acne. 929 37

The morphological and functional development of the interstitial gland was studied in crossbred ewe lambs (East Friesian x Black-Head Pleven breeds) first birth and then at 1, 2, 3, 4, 5, 5.5 and 6 months, as well as at 1 year in anestrous ewes. Histological and histochemical (AP, NAD.H2-tetrasole reductase, G-6-PDH and delta(5)-3 beta-hydroxysteroid dehydrogenase (delta(5)-3 beta-HSD)) methods and transmission electron microscopy (TEM) were applied while the FSH and LH levels were measured. There was an abundance of epithelial cell cords in newborn animals, while interstitial cells were scanty. Cortical and medullary epithelial cell cords occupied an essential place in the histogenesis of ovine ovarian structures. They were clearly expressed during the whole postnatal period of the development, and showed a species specificity. The development of the interstitial gland was correlated with changes in the gonadotropic hormones. A new population of interstitial glands appeared around puberty in a similar manner to the so-called 'puberty gland' in the testis and ovary of humans and other mammals. The results suggest that in these crossbred lambs, puberty was attained between the 3rd and 4th month, and sexual maturity and 5 to 6 months of age.
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PMID:The interstitial gland of ovary of ewes from birth to sexual maturity. 945 76

Hydroxymethylglutaryl-Coenzyme A (HMG-CoA) reductase is a highly regulated enzyme which shows a marked circadian rhythmicity. We studied the impact of aging on this rhythm as well as the degree of correlation between age changes in circulating pituitary hormone levels and liver reductase activity in young (4 months) and old (33 months) Sprague-Dawley female rats. Lipid composition was also assessed in plasma and liver microsomes. The maximal activity (midnight) of HMG-CoA reductase fell from 864 +/- 28 pmol mevalonate/min/mg protein in the young rats to 552 +/- 45 pmol/min/mg protein in the old animals, whereas significant change was not observed in the basal (noon) activity levels of the enzyme. Noon serum cholesterol, but not midnight values, was significantly higher in the old rats. Liver cholesterol levels were similar in young and old rats. In old rats, fatty acid composition of liver microsomes revealed an increase in linoleic acid concurrently with a significant decrease in arachidonic acid (AA). A significant correlation was not detected between the age changes in pituitary hormone (GH, PRL, TSH, FSH) serum levels and those in reductase activity. On the other hand, a significant positive correlation was found in the old rats between hepatic reductase activity and the severity of mammary pathology. We conclude that, like most biological rhythms, HMG-CoA reductase circadian fluctuation decreases in amplitude with age. This change does not seem to be linked to the alterations of neuroendocrine function associated with the aging process. The presence of growing mammary tumors seems to stimulate liver reductase activity, which may constitute an adaptive response of the enzyme to cholesterol demand by the growing neoplastic tissue.
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PMID:Age changes in the activity of liver 3-hydroxy-3-methylglutaryl-CoA reductase in female rats: influence of mammary pathology. 950 93

Androgenetic alopecia especially that with premature onset can be a cause of serious psychic trauma. As far as the treatment with antiandrogens, inhibitors of 5 alpha-reductase or hair transplantation represents a heavy economic burden for the patient, we tried to exclude other hormonal causes or to find a criterion for the apt candidates for the treatment in 15 young men with premature androgenetic alopecia. Hormonal analysis discovered a significantly lower plasma level of sexual binding globulin (SHBG) and FSH and nearly significantly higher concentration of 17 alpha-hydroxyprogesterone. These data resemble those in the hormonal pattern of women suffering from the syndrome of polycystic ovaries (PCOS). The finding of premature balding as the possible male phenotype hormonal equivalent of polycystic ovaries is in concordance with several pedigree studies in kindreds with PCOS, which have suggested a genetic basis of this syndrome in some families in which balding and pilosity was frequent in male members.
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PMID:[Hormonal profile in men with premature androgenic alopecia]. 1095 26

This article summarizes a talk on Leydig cell aging presented at the 1999 Annual Meeting of the Society for the Study of Reproduction. In the Brown Norway rat, serum testosterone levels decrease with aging, accompanied by increases in serum FSH. The capacity of Leydig cells to produce testosterone is higher in young than in old rats. Binding studies with hCG revealed reduced receptor number in old vs. young Leydig cells. In response to incubation with LH, cAMP production was found to be reduced in old vs. young Leydig cells, indicating that signal transduction mechanisms in the old cells are affected by aging. Steroidogenic acute regulatory protein and mRNA levels are reduced in old Leydig cells, suggesting that there may be deficits in the transport of cholesterol to the inner mitochondrial membrane of aged cells. The activity of P450 side-chain cleavage enzyme is reduced in old vs. young cells, as are the activities of each of 3beta-hydroxysteroid dehydrogenase, 17alpha-hydroxylase/C17-20 lyase, and 17-ketosteroid reductase. Serum LH levels do not differ between young and old rats, and the administration of LH failed to induce old Leydig cells to produce high (young) testosterone levels, suggesting that the cause of age-related reductions in steroidogenesis is not LH deficits. We hypothesized that reactive oxygen, produced as a by-product of steroidogenesis itself, might be responsible for age-related reductions in testosterone production by the Leydig cells. Consistent with this, long-term suppression of steroidogenesis was found to prevent or delay the reduced steroidogenesis that accompanies Leydig cell aging. A possible explanation of this finding is that long-term suppression of steroidogenesis prevents free radical damage to the cells by suppressing the production of the reactive oxygen species that are a by-product of steroidogenesis itself.
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PMID:Regulation of Leydig cell steroidogenic function during aging. 1099 16

The MVDP (mouse vas deferens protein) gene encodes an aldose reductase-like protein (AKR1B7) highly expressed in vas deferens epithelium and zona fasciculata of the adrenal cortex. Recombinant MVDP showed kinetic properties distinct from those of aldose reductase, including its spectrum of substrates, cofactor preference and sensitivity to inhibitors. We demonstrate that in adrenocortical cells, MVDP, rather than aldose reductase, is the principal reductase for isocaproaldehyde (a product of side-chain cleavage of cholesterol) and 4-hydroxynonenal (a lipid peroxidation product). In steroidogenic tissues MVDP expression is regulated by pituitary trophic hormones, namely ACTH in adrenals, FSH in ovaries, and LH in testicular Leydig cells.
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PMID:Physiological functions and hormonal regulation of mouse vas deferens protein (AKR1B7) in steroidogenic tissues. 1130 5

Hypertrichosis, characterized by increased hair growth located in non-androgen-dependent areas, does not justify the monitoring of hormone levels, conversely to hirsutism, with increased hair growth in androgen-dependent areas of the female genitals. Adult hypertrichosis is iatrogenic (minoxidil, ciclosporine, diazoxide or glucocorticosteroids), of metabolic origin (porphyria), nutritional (anorexia) or paraneoplastic (hypertrichosis lanuoginosa). Metabolic or general assessment can help clinical diagnosis. In non-iatrogenic hirsutism the following must be eliminated: 1) a virilizing tumor (ovarian, adrenal) when confronted with rapid progression or recent hirsutism, plasma testosterone (T)>1.5ng/ml and/or (adrenal tumor) DHEA-sulfate (DHEAS)>700 microgram/dl and associated with hypertension; 2) when confronted with characteristic signs of hirsutism, Cushing's syndrome (post-dexamethasone cortisol), hyperprolactinemia (pooled PRL), or acromegalia (IGF1). Measurement of 17-OH-progesterone at 8 am on the 4th day of the cycle detects the late manifestation homozygous forms of a 21-hydroxylase (21OHD) block. The more frequent forms are: 1) ovarian polymicrocystic or hirsutism-anovulation syndromes without other causes (LH/FSH, T, hyperinsulinemia, sonography); 2) functional adrenal hyperandrogenia (increased DHEAS without organic cause); 3) idiopathic hirsutism. Treatment can be local (discoloration, depilation, diathermo-coagulation, laser). Treatment of hirsutism of organic origin is etiologic. The inhibitory effects of glucocorticosteroids are mediated by 21OHD. The most effective treatments are anti-androgenic: cyproterone acetate, progesterone-like and anti-gonadotropic (contraceptive) agents; and the only product in France officially indicated in hirsutism , spironolactone (anti-mineralocorticosteroid); and flutamide, pure anti-androgen (probably hepatoxic). Finasteride (type II 5 alpha-reductase inhibitor) appears less effective. Estrogen-progestagen-like agents can be associated with anti-androgens. We should also mention the GnRH-agonists, and finally, dietetics and metformine (in cases of insulin-resistance).
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PMID:[Hirsutism and hypertrichosis in adults: investigations and treatment]. 1222 63

This study describes a model for short-term culture of intact mouse follicles under serum-free conditions. Follicles were either obtained from immature mice receiving no ovarian stimulation (i.e. no eCG-primed protocol, group I) or from mice undergoing ovarian stimulation (i.e. eCG-primed protocol, group II). Follicles were grouped according to size (100-170, 180-200, 210-250, 260-350 and 360-400 microm, respectively) and cultured for 24h (group I) or for only 6h (group II). Induced meiotic resumption of follicle-enclosed oocytes were evaluated following stimulation with gonadotropins (i.e. FSH and hCG), AY9944-A-7, an inhibitor of Delta14-reductase, and RS-21745, an inhibitor of lanosterol 14alpha-demethylase; both enzymes affect synthesis of the meiosis activating sterols (MAS) that induce oocyte maturation. The frequency of oocyte degeneration was also recorded. In group I, FSH (10-200 IUl-1) and AY9944-A-7 (5, 25 and 50 microM) separately induced resumption of meiosis in oocytes derived from follicles with a diameter of 180-400 microm. hCG (1.0 and 10 IUml-1) exhibited a similar but weaker effect on oocytes present in follicles with a diameter of 260-400 microm. Irrespective of follicular diameter oocytes obtained from follicles in group II responded to hCG and FSH by resuming meiosis. FSH (50 IUl-1) alone or hCG (10 IUml-1) alone both increased the GVBD percentage of oocytes enclosed in follicles with a diameter 260-400 microm, but the response to hCG was not significant compared to control. FSH (50 IUl-1) combination with hCG (10 IUml-1) showed an additive effect raising the rate of GVBD after 6h culture. Addition of 50 or 100 microM RS-21745 was able to attenuate gonadotropins-induced resumption of meiosis to below background levels. In conclusion, the ability of FSH to induce meiotic resumption of follicle-enclosed mouse oocytes is correlated to follicle size, being most pronounced in larger follicles. hCG caused a similar but less pronounced effect. The ability of RS-21745 to inhibit and the ability of AY9944-A-7 to enhance oocyte maturation of follicle-enclosed oocytes support the concept of FSH employing MAS as a downstream signal transduction molecule for initiation of oocyte maturation in mice.
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PMID:Roles of gonadotropins and meiosis-activating sterols in meiotic resumption of cultured follicle-enclosed mouse oocytes. 1513 May 20


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