Granulosa cell

From Infogalactic: the planetary knowledge core
Jump to: navigation, search
File:Pig oocyte dapi 4.jpg
Pig oocyte surrounded by granulosa cells. Fluorescence microscopy, colored with DAPI.

A granulosa cell or follicular cell is a somatic cell of the sex cord that is closely associated with the developing female gamete (called an oocyte or egg) in the ovary of mammals.

Structure and function

In the primary ovarian follicle, and later in follicle development (folliculogenesis), granulosa cells advance to form a multilayered cumulus oophorus surrounding the oocyte in the preovulatory or antral (or Graafian) follicle.

The major functions of granulosa cells include the production of sex steroids, as well as myriad growth factors thought to interact with the oocyte during its development. The sex steroid production consists of follicle-stimulating hormone (FSH) stimulating granulosa cells to convert androgens (coming from the thecal cells) to estradiol by aromatase during the follicular phase of the menstrual cycle.[1] However, after ovulation the granulosa cells turn into granulosa lutein cells that produce progesterone. The progesterone may maintain a potential pregnancy and causes production of a thick cervical mucus that inhibits sperm entry into the uterus.

Embryology of ovarian granulosa cells

In the development of the urinary and reproductive organs, the oogonia become invaginated in the gonadal ridge.

The embryological origin of granulosa cells remains controversial. In the 1970s, evidence emerged that the first cells to make contact with the oogonia were of mesonephric origin. It was suggested that mesonephric cells already closely associated with the oogonia proliferated throughout development to form the granulosa cell layer.[2][3][4] Recently, this hypothesis has been challenged with some thorough histology. Sawyer et al. hypothesized that in sheep most of the granulosa cells develop from cells of the mesothelium (i.e., epithelial cells from the presumptive surface epithelium of the ovary).[5] In 2013 it was proposed that both granulosa cells and the ovarian surface epithelial cells are instead derived from a precursor cell called Gonadal-Ridge Epithelial-like cell. [6]

Cell culture

Cell culture of granulosa cells can be performed in vitro. Plating density (number of cells per volume of culture medium) plays a critical role for the differentiation. A lower plating density makes granulosa cells exhibit estrogen production, while a higher plating density makes them appear as progesterone producing theca lutein cells.[7]

Additional images

Lua error in package.lua at line 80: module 'strict' not found.

See also

References

  1. Lua error in package.lua at line 80: module 'strict' not found.
  2. Lua error in package.lua at line 80: module 'strict' not found.
  3. Lua error in package.lua at line 80: module 'strict' not found.
  4. Zamboni, L., Bezard, J., and Mauleon, P. (1979). The role of the mesonephros in the development of the sheep fetal ovary. Annales de Biologie Animal Biochimie et Biophysique 19, 1153-78.
  5. Lua error in package.lua at line 80: module 'strict' not found.
  6. Lua error in package.lua at line 80: module 'strict' not found.
  7. Lua error in package.lua at line 80: module 'strict' not found.

External links


<templatestyles src="Asbox/styles.css"></templatestyles>