Follicle-stimulating hormone
[1] FSH is synthesized and secreted by the gonadotropic cells of the anterior pituitary gland[2] and regulates the development, growth, pubertal maturation, and reproductive processes of the body.
[3] FSH is a 35.5 kDa glycoprotein heterodimer, consisting of two polypeptide units, alpha and beta.
[6] The sugar portion of the hormone is covalently bonded to asparagine, and is composed of N-acetylgalactosamine, mannose, N-acetylglucosamine, galactose, and sialic acid.
The gene for the FSH beta subunit is located on chromosome 11p13, and is expressed in gonadotropes of the pituitary cells, controlled by GnRH, inhibited by inhibin, and enhanced by activin.
[8] FSH regulates the development, growth, pubertal maturation and reproductive processes of the human body.
The cohort of small antral follicles is normally sufficient in number to produce enough Inhibin B to lower FSH serum levels.
[14] When the follicle matures and reaches 8–10 mm in diameter it starts to secrete significant amounts of estradiol.
The sharp increase in estradiol production by the dominant follicle (possibly along with a decrease in gonadotrophin surge-attenuating factor) cause a positive effect on the hypothalamus and pituitary and rapid GnRH pulses occur and an LH surge results.
Occasionally two follicles reach the 10 mm stage at the same time by chance and as both are equally sensitive to FSH both survive and grow in the low FSH environment and thus two ovulations can occur in one cycle possibly leading to non-identical (dizygotic) twins.
The most common reason for high serum FSH concentration is in a female who is undergoing or has recently undergone menopause.
This condition is typically manifested in males as failure in production of normal numbers of sperm.
This presents possible use of FSH and FSH-receptor antagonists as an anti-tumor angiogenesis therapy (cf.
- The ranges denoted By biological stage may be used in closely monitored menstrual cycles in regard to other markers of its biological progression, with the time scale being compressed or stretched to how much faster or slower, respectively, the cycle progresses compared to an average cycle.
- The ranges denoted Inter-cycle variability are more appropriate to use in non-monitored cycles with only the beginning of menstruation known, but where the woman accurately knows her average cycle lengths and time of ovulation, and that they are somewhat averagely regular, with the time scale being compressed or stretched to how much a woman's average cycle length is shorter or longer, respectively, than the average of the population.
- The ranges denoted Inter-woman variability are more appropriate to use when the average cycle lengths and time of ovulation are unknown, but only the beginning of menstruation is given.