Ovarian follicle atresia
Encyclopedia
Ovarian follicle atresia is the periodic process in which immature ovarian follicles degenerate and are subsequently re-absorbed during the follicular phase of the menstrual cycle. Typically around 20 follicles mature each month and only a single follicle is ovulated. The rest undergo atresia. That single dominant follicle becomes a corpus luteum
following ovulation.
Atresia is a hormonally
controlled apoptotic
process that depends dominantly on granulosa cell apoptosis.
To date, at least five cell-death ligand-receptor systems have been reported in granulosa cells to play a role in atresia regulation . They are:
In addition, two intracellular inhibitor proteins, cellular FLICE-like inhibitory protein
short form (cFLIPS) and long form (cFLIPL), which were strongly expressed in granulosa cells, may act as anti-apoptotic factors.
It has been proposed that enhanced levels of Nitrogen oxide
in rats can prevent atresia of the ovarian follicle, and depressed levels have the opposite effect.
Corpus luteum
The corpus luteum is a temporary endocrine structure in mammals, involved in production of relatively high levels of progesterone and moderate levels of estradiol and inhibin A...
following ovulation.
Atresia is a hormonally
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...
controlled apoptotic
Apoptosis
Apoptosis is the process of programmed cell death that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation...
process that depends dominantly on granulosa cell apoptosis.
To date, at least five cell-death ligand-receptor systems have been reported in granulosa cells to play a role in atresia regulation . They are:
- tumor necrosis factor alpha (TNF alpha) and receptors
- Fas ligand and receptors
- TNFTumor necrosis factorsTumor necrosis factors refers to a group of cytokines family that can cause cell death . The first two members of the family to be identified were:...
-related apoptosisApoptosisApoptosis is the process of programmed cell death that may occur in multicellular organisms. Biochemical events lead to characteristic cell changes and death. These changes include blebbing, cell shrinkage, nuclear fragmentation, chromatin condensation, and chromosomal DNA fragmentation...
-inducing ligand (TRAIL; also called APO-2) and receptors - APO-3 ligand and receptors
- PFG-5 ligand and receptors
In addition, two intracellular inhibitor proteins, cellular FLICE-like inhibitory protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
short form (cFLIPS) and long form (cFLIPL), which were strongly expressed in granulosa cells, may act as anti-apoptotic factors.
It has been proposed that enhanced levels of Nitrogen oxide
Nitrogen oxide
Nitrogen oxide can refer to a binary compound of oxygen and nitrogen, or a mixture of such compounds:* Nitric oxide, also known as nitrogen monoxide, , nitrogen oxide* Nitrogen dioxide , nitrogen oxide...
in rats can prevent atresia of the ovarian follicle, and depressed levels have the opposite effect.