Question

The gonadotropin hormones are secreted by?

Answer 1

Gonadotropins are peptide hormones that regulate ovarian and testicular function and are essential for normal growth, sexual development, and reproduction. The human gonadotropin hormones include follicle-stimulating hormone (FSH) and luteinizing hormone (LH) and chorionic gonadotropin (hCG).

Complete answer:
All three gonadotropins ie LH, FSH, and HCG are heterodimeric proteins that consist of two peptide chains, the alpha chain is similar in all three, whereas the beta chain is unique and it is different in all the three gonadotropins and it determines the fine receptor specificity and function of each hormone.
The pituitary gonadotropins are under the direct control of gonadotropin-releasing hormone (GnRH), it is a decapeptide produced in the hypothalamus and released in response to circulating levels of estrogens and progesterone in the blood.
1. Follicle-stimulating hormone (FSH): It is a pituitary hormone that regulates growth, sexual development, and reproduction, including menstruation, follicular development, and ovulation. FSH is regulated, by GnRH produced in the hypothalamus in response to multiple signals including circulating levels of sex hormones ie estrogen, and progesterone.
2. Luteinizing hormone (LH): It is a pituitary hormone that is essential for sexual development and reproduction in both men and women. LH is also regulated by GnRH from the hypothalamus which is sensitive to circulating levels of sex hormones in the blood. LH interacts with receptors on ovarian follicles and promotes their maturation. In the middle of the menstrual cycle, a surge of LH hormone triggers ovulation and production of progesterone by the corpus luteum. In males, LH stimulates the production of testosterone in the testes.
3. Human chorionic gonadotropin (HCG) is a polypeptide hormone produced by the placenta following implantation. Circulating human chorionic gonadotropin interacts with the luteinizing hormone (LH) receptors of the ovary, promoting the corpus luteum and its production of progesterone which is necessary to maintain pregnancy and support the fetus growth.

Note:
GnRH activity is low during childhood and increases markedly during puberty, synthetic forms of GnRH have been used with the gonadotropins in assisted reproductive techniques and in vitro fertilization, in high doses, the gonadotropins can induce ovarian hyperstimulation syndrome (OHSS) which may be accompanied by liver test abnormalities, jaundice, edema, and ascites.LH is used clinically in assisted reproduction techniques (ART) and in IVF (in vitro fertilization) to stimulate ovarian follicle maturation.