This extended description was generated by ChatGPT and reviewed by the CellGuide team, who added references, and by the CL editors, who approved it for inclusion in CL. It may contain information that applies to only to some subtypes and species, and so should not be considered definitional. Granulosa cells are a type of somatic cell most commonly known for their crucial role within the ovarian follicles of female mammalian species. Named for their grainy appearance, they are situated in the follicular epithelium, lining the inner part of the follicle and directly surrounding the oocyte. These cells stand as an integral part of the ovarian structure and function. One of the primary roles of granulosa cells is to aid in the production and secretion of sex hormones, particularly estrogen. They achieve this by working in tandem with theca cells, which stay attached to the external layer of the follicle. Theca cells produce androstenedione (a type of androgen) which granulosa cells then convert into estradiol, a form of estrogen, with the help of the enzyme aromatase. Moreover, granulosa cells participate in luteinization, transforming into luteal granulosa cells as a response to the luteinizing hormone during ovulation. This allows the formation of the corpus luteum, responsible for the secretion of progesterone necessary to maintain pregnancy. Granulosa cells also play a significant role in follicular development and oocyte maturation, involving close communication with the contained oocyte. They support the oocyte through the provision of nutrients and growth factors, control its meiotic cycle and ensure it is appropriately oriented and instructed for impending ovulation. Furthermore, granulosa cells contribute to the formation of the zona pellucida and the follicular fluid, providing an optimal environment for the oocyte's growth and maturation. These cells, thus, perform multiple vital roles, underscoring their importance in fertility and reproductive health.

CALOHA:TS-0729

BTO:0000542

ZFA:0009227

NCIt:C12587

FMA:18718

TO:0000542

A supporting cell for the developing female gamete in the ovary of mammals. They develop from the coelomic epithelial cells of the gonadal ridge. Granulosa cells form a single layer around the mammalian oocyte in the primordial ovarian follicle and advance to form a multilayered cumulus oophorus surrounding the ovum in the Graafian follicle. The major functions of granulosa cells include the production of steroids and LH receptors.

granulosa cell of ovary

granulosa cell

granulosa cell

CL:0000501

granulosa cell