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Regulation of Reproduction by Dopamine
Published in Nira Ben-Jonathan, Dopamine, 2020
Ovarian steroids are critical for normal uterine function, for the establishment and maintenance of pregnancy, mammary gland development, and for the support of the female secondary sex characteristics. In most mammals (including humans) ovarian steroidogenesis occurs by a two-hormone/two-cell mechanism. Under this paradigm, the two gonadotropins, LH and FSH, and two cell types, theca and granulosa, work coordinately to produce the ovarian steroids. Theca cells, which are derived from the ovarian stroma, differentiate into endocrine cells under the influence of the growing dominant follicle (Figure 10.12A). The main steroidal product of the follicle is estrogen, while progesterone is the main product of the corpus luteum.
Herbal Management for Polycystic Ovarian Syndrome
Published in Megh R. Goyal, Hafiz Ansar Rasul Suleria, Ademola Olabode Ayeleso, T. Jesse Joel, Sujogya Kumar Panda, The Therapeutic Properties of Medicinal Plants, 2019
Huma Bader-Ul Ain, Farhan Saeed, Muhammad Umair Arshad, Hafiz Ansar Rasul Suleria
According to Dunne and Slater [39], motivators of PCOS are many hormones such as testosterone-producing androgen, cortisol, estrogens (female hormone), FSH, insulin (carrier of blood glucose to other cells), LH, progesterone (female hormone), prolactin, and thyroid hormones disturbances. In retort to prompt by LH, the ovarian theca-cells amalgamate androgens. It is revealed from in-vitro and in-vivo studies that chances of conversion of androgenic signs into testosterone are higher in case of PCOS women with abnormal theca cells in their ovaries as compared to normal women with normal theca cells [114].
Endocrine characteristics of assisted reproduction technology cycles
Published in David K. Gardner, Ariel Weissman, Colin M. Howles, Zeev Shoham, Textbook of Assisted Reproductive Techniques, 2017
Bulent Urman, Baris Ata, Hakan Yarali
Progesterone is synthesized mainly by the ovary and, to a much lesser extent, by the adrenal gland. Both the granulosa and theca cells synthesize progesterone (Figure 41.2). However, C17 hydroxylase activity is only present in theca cells and hence progesterone produced by the granulosa cells diffuses into the theca cells to be hydroxylated; alternatively, progesterone produced by granulosa cells may acquire access to the circulation if produced in excess amounts (Figure 41.2). Progesterone in theca cells is metabolized into androgens and subsequently aromatized to estrogens back in the granulosa cells.
CircEpha5 regulates the synthesis and secretion of androgen in mouse preantral follicles by targeting miR-758-5p
Published in Journal of Obstetrics and Gynaecology, 2023
Xueying Zhang, Jiaxuan Liu, Hao Wu, Yan Chen, Xuesen Zhang, Boqun Xu
It has been reported that most PCOS patients with hyperandrogenism exhibit steroid secretion defects, which can lead to abnormal folliculogenesis and a failure in dominant follicle selection (Zeng et al.2020). For example, overexpression of steroidogenesis acute regulator (StAR) in PCOS exhibited a state of hyperandrogenism (Kalyani et al.2018). The elevation of luteinizing hormone receptor (LHR) promotes the conversion of cholesterol into testosterone and androsterone, thus stimulating ovarian theca cells to produce excessive androgen (Ritu et al.2019). Studies have shown that CAG repeat polymorphisms in androgen receptor (AR) gene may cause hyperandrogenemia in PCOS (Ryan et al.2018). Theca cells from polycystic ovaries of classic PCOS patients overexpress most steroidogenic enzymes. Cytochrome P450 cholesterol side chain lyase (P450c11, encoded by CYP11A1 gene), catalyses the conversion of cholesterol to progesterenolone during steroid hormone synthesis. Cytochrome P450 17 A-hydroxylase and 17 and 20 carbon chain lyase (P450c17, CYP17A1 gene code) are rate-limiting enzymes for androgen production in the ovary and adrenal cortex (Belani et al.2018). The expression of enzymes related to androgen biosynthesis increases in follicular membrane cells of PCOS mice, and the level of testosterone also rises in the culture medium of PCOS follicular membrane cells (Jakimiuk et al.2001, Madeleine et al.2018). Studying the synthesis and secretion of androgen in follicles may provide new insight into the pathogenesis of PCOS hyperandrogenemia.
The reproductive endocrine feature and conception outcome of women with unknown etiological menstrual cycle (36–45 days) with long follicular phase
Published in Gynecological Endocrinology, 2022
Zhewei Wang, Jiongjiong Yan, Huifen Chen, Laman He, Shaohua Xu
The hypothalamic–pituitary–ovarian axis (HPOA) mainly affects the development of follicles. Adversely, the abnormality in the amount or the cyclicity of sexual hormones secreted by the ovary is either not enough to stimulate follicular stimulating hormone (FSH) secretion, or cannot reach the peak of luteinizing hormone (LH) secretion during ovulation leading to the slow development of follicles and ovulation disorder. Ovarian local regulatory factors INH (inhibin), ACT (activin), and FS (follistatin) also play crucial roles in follicle recruitment and the selection of dominant follicles. INH regulates follicle-stimulating synthesis and release of FSH and stimulates the biosynthesis of androgen by theca cells. ACT enhances the expression of the FSH receptor, improves FSH secretion, and inhibits effect of LH on androgen secretion. FS is a binding protein of ACT and INH, which inhibits the aromatase activity of granulosa cells and resists effect of ACT on follicles. The abnormality of INH–ACT–FS system leads to the failure of oocyte maturation. INH is a heterodimer glycoprotein hormone formed by the disulfide bond between an α subunit and one kind of ß subunits (ßA, ßB) and INHB (α-ßB)is mainly in pre-ovulatory follicles. ACT consists of two kinds of ß subunits and the main active form is ACTA (ßAßA). Therefore, we evaluated the ratio of FSH/LH and INHB, ACTA, and FS.
FSHR antagonists can trigger a PCOS-like state
Published in Systems Biology in Reproductive Medicine, 2022
Faiza Hanif Waghu, Karishma Desai, Sumana Srinivasan, Kaushiki S. Prabhudesai, Vikas Dighe, Kareenhalli V. Venkatesh, Susan Idicula-Thomas
In ovaries, during the progression of folliculogenesis from pre-antral to antral stage, theca cells differentiate to express LHCGR (Orisaka et al. 2009; Young and McNeilly 2010). Interaction of LH with LHCGR on theca cells induces expression of a microsomal enzyme, CYP17A1, that is a major regulator of androgen production. Under the influence of 17α-hydroxylase activity of CYP17A1 enzyme, pregnenolone, a precursor of steroids is converted to 17 α-hydroxypregnenolone. This is further cleaved through 17,20-lyase (lyase) activity of CYP17A1 enzyme to form dehydroepiandrosterone which gets converted into T and dihydrotestosterone (Maity et al. 2016). Hyperandrogenism in PCOS is attributed to excessive androgen production by theca cells of the ovaries. This theory is supported by observations from in vitro studies, wherein an increased production of androgens was reported from theca cells isolated from women with PCOS (Gilling-Smith et al. 1994; Nelson et al. 1999). Further, Jakimiuk et al. reported higher mRNA levels of LHCGR and CYP17A1 in thecal cells of follicles harvested from women with PCOS as compared to size-matched control follicles (Jakimiuk et al. 2001). Similarly, protein levels of LHCGR and CYP17A1 were found to be elevated in theca cells and antral follicles obtained from women with PCOS (Comim et al. 2013). In concordance with the above reports, we observed higher mRNA levels of Lhcgr and Cyp17a1 in ovaries of peptide-treated rats as compared to ovaries of vehicle-treated rats (Figure 1).