NCBI Summary:
The enzyme 3-beta-hydroxysterol delta-24-reductase (DHCR24), a member of the flavin adenine dinucleotide (FAD)-dependent oxidoreductases, catalyzes the reduction of the delta-24 double bond of sterol intermediates during cholesterol biosynthesis.[supplied by OMIM]
General function
Enzyme
Comment
Cellular localization
Cytoplasmic
Comment
Ovarian function
Steroid metabolism
Comment
Genes in sterol/steroid and lipid biosynthetic pathways are targets of FSH and FOXO1 regulation in granulosa cells: evidence from cells expressing mutant forms of FOXO1. Liu Z et al. The forkhead box transcription factor FOXO1 is highly expressed in granulosa cells of growing follicles but is down-regulated by FSH in culture or by LH-induced luteinization in vivo. To analyze the function of FOXO1, we infected rat and mouse granulosa cells with adenoviral vectors expressing two FOXO1 mutants: a gain-of-function mutant FOXOA3 that has three serine residues mutated to alanines rendering this protein constitutively active and nuclear and FOXOA3-mDBD in which the DNA binding domain is mutated. The infected cells were then treated with vehicle or FSH for specific time intervals. Infection of the granulosa cells was highly efficient, caused only minimal apoptosis and maintained FOXO1 protein at levels of the endogenous protein observed in cells prior to exposure to FSH. RNA was prepared from control and adenoviral infected cells exposed to vehicle or FSH for 12 and 24h. Affymetrix microarray and data-base analyses identified, and real time RT-PCR verified, that genes within the lipid, sterol and steroidogenic biosynthetic pathways (Hmgcs1, Hmgcr, Mvk, Sqle, Lss, Cyp51, Tm7sf2, Dhcr24 and Star, Cyp11a1 and Cyp19), including two key transcriptional regulators Srebf1 and Srebf2 of cholesterol biosynthesis and steroidogenesis (Nr5a1, Nr5a2) were major targets induced by FSH and suppressed by FOXOA3 and FOXOA3-mDBD in the cultured granulosa cells. By contrast, FOXOA3 and FOXOA3-mDBD induced expression of Cyp27a1 mRNA that encodes an enzyme involved in cholesterol catabolism to oxysterols. The genes up-regulated by FSH in cultured granulosa cells were also induced in granulosa cells of preovulatory follicles and corpora lutea collected from immature mice primed with FSH (eCG) and LH (hCG), respectively. Conversely, Foxo1 and Cyp27a1 mRNAs were reduced by these same treatments. Collectively, these data provide novel evidence that FOXO1 may play a key role in granulosa cells to modulate lipid and sterol biosynthesis, thereby preventing elevated steroidogenesis during early stages of follicle development.
Expression regulated by
leptin
Comment
Role of leptin in the regulation of sterol/steroid biosynthesis in goose granulosa cells. Hu S 2014 et al.
Leptin is critical for reproductive endocrinology. The aim of this study is to assess the expression patterns of leptin receptor (Lepr) during ovarian follicle development and to reveal the mechanism by which leptin affects steroid hormone secretion in goose granulosa cells. Transcripts of Lepr were ubiquitous in all tested tissues, with pituitary and adrenal glands being the predominant sites. Goose ovarian follicles were divided into several groups by diameter including prehierarchical (4 to 6, 6 to 8, and 8 to 10mm) and hierarchical (F5-F1) follicles. Lepr gene expression was significantly higher in granulosa cells than in theca cells from follicles of 4 to 8mm in diameter. Expression of Lepr in granulosa cells decreased gradually as follicles developed, with fluctuating expression in F5 and F3 follicles. Lepr mRNA in theca cells underwent a slight decrease from the 6- to 8-mm cohorts to F5 follicle and then exhibited a transient increase and declined later. Invitro experiments in cultured goose granulosa cells showed that estradiol release was significantly stimulated, whereas progesterone increased slightly and testosterone decreased dramatically after leptin treatment. In accordance with the data for steroids, expression of Lepr, Srebp1, Cyp51, StAR, and Cyp19a1 were induced by the addition of leptin, and the concomitant changes in Hmgcs1, Dhcr24, Cyp11a1, 17-hsd, Cyp17, and 3-hsd gene expression were seen. These results suggested that leptin is involved in the development of goose ovarian follicles, and leptin's effect on steroid hormone secretion could be due to altered sterol/steroidogenic gene expression via interaction with its receptor.
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Ovarian localization
Comment
Seladin-1/DHCR24 expression in normal ovary, ovarian epithelial and granulosa tumours Fuller PJ, et al .
Summary Objective The human DIMINUTO/DWARF1 homolog seladin-1/DHCR24 has been recently reported to be up-regulated in adrenocortical adenomas. Seladin-1 expression has been reported in the normal ovary. Granulosa cell tumours of the ovary (GCT) as with adrenocortical adenomas arise from a steroidogenic tissue, respond to pituitary hormone stimulation and synthesize steroid hormones. Design To test the hypothesis that seladin-1 may also have a role in the pathogenesis of GCT, we determined the expression of seladin-1 in a cohort of GCT and in mucinous and serous cystadenocarcinomas and in normal ovary. Measurements Expression was determined by RT-PCR using gene specific primers and probes combined with Southern blot analysis of the PCR products. Results Seladin-1 expression was identified in the normal ovary, mucinous cystadenocarcinomas and serous cystadenocarcinomas of the ovary whereas no expression was observed in the GCT. Conclusions Based on our results, seladin-1 is not expressed in the granulosa cells or at least not in those that give rise to GCT.
Follicle stages
Comment
Phenotypes
Mutations
1 mutations
Species: mouse
Mutation name: None
type: null mutation fertility: infertile - ovarian defect Comment:Wechsler A, et al reported the generation of viable cholesterol-free mice. The feamles were infertile.