Follitropin is a follicle-stimulating hormone (FSH) produced in the pituitary gland of mammals. In females, it encourages the growth of ovarian follicles and the production of eggs. For males, it acts on the testes to produce sperm. Medically, this hormone is generally used address fertility problems.
A person's hormonal system is tightly regulated by three interdependent mechanisms. Follitropin plays a direct role in one feedback loop. In females, FSH stimulates the growth of ovarian follicles and, consequently, the production of estrogen. Increasing levels of estrogen will cause less FSH to be produced. The levels of FSH and estrogen in the bloodstream maintain a dynamic balance.
Urofollitropin is a purified form of human FSH extracted from urine of postmenopausal women. Follitropin alpha and beta are synthetic hormones produced by recombinant DNA (rDNA) technology. Two human DNA sequences for the production of FSH are inserted into a hamster ovarian cell line. The resulting hormone is functionally indistinguishable from human FSH. Each of these three forms of the hormone serves as the basis for a pharmaceutical product.
Clinical trials have compared the efficacy of these products. No significant difference was found in the effectiveness of the synthetic forms. One study concluded that the human derived form and follitropin beta had comparable efficiency in controlled ovarian stimulation intended to produce multiple eggs.
A high level of FSH during the reproductive years is abnormal. This could indicate the presence of a condition associated with infertility, such as primary ovarian failure. Unusually low levels of FSH indicate conditions that might result in the cessation of ovulation or an inadequate sperm count. Those suffering from low FSH levels might benefit from medical treatment that includes follitropin.
In men, raising low FSH levels can increase the production of sperm. Used in combination with other hormones, follitropin has been successfully used to treat women with ovulation problems. Treatment has been particularly effective in cases where the ovarian follicles were otherwise healthy, but had not been sufficiently stimulated to mature. Follitropin has also been used to encourage the development of multiple eggs for use in procedures such as in vitro fertilization (IVF).
Women who suffer from ovarian failure, hormone-sensitive tumors or uncontrolled thyroid or adrenal problems are usually not suitable candidates for this type therapy. The same is true for men who exhibit normal pituitary function, primary testicular failure or any infertility other than that caused by a lack of FSH. Sensitivity to recombinant DNA products would effectively rule out treatment involving the synthetically produced alpha and beta versions of this hormone, as well.