Gametogenesis
Frank J. Dye in Human Life Before Birth, 2019
As the oocyte develops in the ovary, it becomes associated with a number of somatic cells called follicle cells (or granulosa cells). Collectively, the germ cell and follicle cells make up an ovarian follicle (Figure 6.7). The oocyte surrounded by a single layer of follicle cells is called a primary follicle; two or more layers of follicle cells result in a secondary follicle. When fluid-filled spaces (antral vacuoles) begin to appear among the follicle cells, it is called a tertiary follicle. As the follicle matures, it moves to the surface of the ovary and causes the ovarian surface to bulge outward in a papilla. At this stage, we have a mature follicle (or Graafian follicle) containing a primary oocyte about to complete meiosis I and undergo ovulation (see Figure 5.10).
Ovotoxic Environmental Chemicals: Indirect Endocrine Disruptors
Rajesh K. Naz in Endocrine Disruptors, 2004
During fetal development, primordial germ cells (oogonia) that are formed invade the indifferent gonad and undergo rapid hyperplasia. Oogonia become oocytes, once they stop dividing and become arrested at the diplotene stage (prophase) of the first meiotic division. The oocyte does not commence meiosis again unless triggered to ovulate, should that occur. As a result, the lifetime supply of oocytes is set at the time of birth. Around the time of birth, individual oocytes within the ovary become surrounded by a single layer of flattened somatic cells (pre-granulosa cells) and a basement membrane to form primordial follicles.[4] Association of the granulosa cells with the oocyte is critical at all subsequent times for maintenance of viability, and follicle growth and development.[13]
Regulation of Reproduction by Dopamine
Nira Ben-Jonathan in Dopamine, 2020
The ovarian follicles constitute the basic female reproductive units, with each follicle containing a single ovum (egg) arrested in meiosis. Oogenesis is the process that produces mature ova from primordial germ cells. As illustrated in Figure 10.11A, the first few steps in oogenesis, up to the point of generating primary oocytes, occur prenatally. Because primary oocytes do not divide further, a woman is born with all of the oocytes that she will ever have during her life. Oocyte development occurs within a follicle, and oogenesis and folliculogenesis work in tandem (Figure 10.11B). Granulosa cells that surround the oocyte produce important growth factors and supporting substances that facilitate oocyte development and vice versa.
Chao Nang Qing prescription promotes granulosa cell apoptosis and autophagy by targeting GATA3
Published in Gynecological Endocrinology, 2023
Lan Luo, Yan Shen, Donghong Ning, Mi Tang, Licen Xie, Qiuman Zheng, Ziting Ouyang
Polycystic ovary syndrome (PCOS) is a complex metabolic condition with endocrine and fertility-related impacts at all stages of life, which probably results from a mismatch between ancient biology and modern lifestyle [1]. The etiology and pathology of PCOS encompass both external and internal factors, such as environmental toxicants, physical and emotional stress, insulin resistance, an excess amount of androgens, and obesity [2]. Moreover, the multiple pathogenic features of PCOS may increase the risks of cardiovascular disease, diabetes mellitus, nonalcoholic fatty liver disease, and other illnesses [3–6]. Granulosa cells are a crucial somatic composition of the ovary that surround oocytes, promote oocyte development, and generate sex steroids and growth factors, overall making a contribution to normal maturation of ovarian follicles and menstrual cycle [7]. However, granulosa cells may abnormally proliferate in the pathogenesis of PCOS, resulting in excess antral follicles and anovulatory infertility [8]. In this condition, promotion of apoptosis may reduce excessive proliferation in granulosa cells to facilitate the treatment of PCOS. Traditional Chinese doctors commonly use herbal formulas or single herbs to treat women with PCOS [9]. Some of the widely used herbal prescriptions for PCOS show regulatory effects on granulosa cell apoptosis [10,11].
Chronic cholestasis is associated with hypogonadism and premature ovarian failure in adult rats (cholestasis causes ovarian hypogonadism)
Published in Ultrastructural Pathology, 2018
Yomna I. Mahmoud
Transmission electron microscopy: Ultrastructural assessment revealed that the ovaries of Sham-operated rats showed no morphological defects. The ovarian surface epithelium consisted of a single layer of cuboidal cells resting on a basal lamina. These cells contained apical microvilli, numerous mitochondria, and large oval and indented nuclei (Figure 4a). Early antral follicles had distinct structural components including the theca externa, theca interna, granulosa cells, and an oocyte. The thecal cells were relatively thin, displaying flattened cells that had elongated spindle-shaped nuclei (Figure 4b). Granulosa cells were arranged in several layers. The basal layer was composed of tall cells resting on a basal lamina (Figure 4b). Other granulosa cells appeared cuboidal with abundant mitochondria, relatively thin cytoplasm and centrally located, ovoid in shape but often indented, euchromatic nucleus (Figure 4c). The inner layer of granulosa cells has thick prolongations that penetrate a smooth and relatively wide zona pellucida. The membrane of the oocyte showed numerous microvilli also penetrating the zona pellucida (Figure 4d). The ooplasm was populated with loosely clustered organelles. Mitochondria appear round or oval, rather dark with small numbers of shelf-like cristae. Cytoplasmic lamellae and electron-lucent vesicular bodies were dispersed throughout the cytoplasm (Figure 4e).
Betaine ameliorates impaired steroidogenesis and apoptosis in mice granulosa cells induced by high glucose concentration
Published in Systems Biology in Reproductive Medicine, 2020
Kosar Abbasi Samie, Mohammad Reza Tabandeh, Mahsa Afrough
Growing evidence (Boots and Jungheim 2015) has shown that aberrant inflammation and cytokine release in diabetes leads to impaired oocyte competence, anovulation, and associated infertility. Based on earlier studies it has been suggested that betaine attenuates the inflammation through suppression of NLRP3 inflammasome activation and inhibition of NF-κB signaling pathway; pathway that governs transcription of several pro-inflammatory genes and triggers apoptosis by activation of caspase-3 in hyperglycemic condition in ovary (Nayki et al. 2016; Zhao et al. 2018). The protective effect of betaine against apoptosis in granulosa cells under hyperglycemic conditions may be attributed to inhibition of such inflammatory pathways. The precise identification of these mechanisms in granulosa cells needs further investigation.
Related Knowledge Centers
- Antral Follicle
- Cumulus Oophorus
- Folliculogenesis
- Ovarian Follicle
- Ovary
- Somatic Cell
- Gamete
- Oocyte
- Sex Cords
- Sex Hormone