Review: Role and regulatory mechanism of inhibin in animal reproductive system

Animal reproduction is based on the production of male and female gametes by the gonads. The entire reproductive process is regulated by various hormones synthesized and released from the hypothalamic-pituitary-gonadal (HPG) axis. The gonads produce sex hormones that directly act on reproductive activity and secrete a glycoprotein hormone called Inhibin (INH), which is one of the key reproductive hormones regulating the reproductive performance of animals.

In 1932, McCullagh found an effective factor named INH that could inhibit pituitary function in aqueous extracts of bovine testis, and he pointed out that a lack of INH would lead to hypopituitarism and excessive secretion of androgens, resulting in prostatic hypertrophy [1]. So far, many studies have confirmed that INH inhibits pituitary function by inhibiting follicle-stimulating hormone (FSH) synthesis and secretion [2,3]. INH is highly expressed in the ovaries of female animals. Two types of INHs with different molecular weights were first extracted from bovine follicular fluid in 1985 [4]. INH is a key factor that affects follicle development, maturation, and release from the ovaries, and it is closely associated with Sertoli cell function and spermatogenesis. Activin (ACT) is a hormone that can promote the secretion of FSH, ACT and it forms an antagonistic regulatory system with INH. Meanwhile, some specific binding proteins, such as follistatin, transforming growth factor β receptor III (TGFBβ3), bone morphogenetic protein (BMP), and Inhibin binding protein (INHBP/p120), are also involved in the regulation of animal reproductive performance. Follistatin is an ACT-binding protein that can inhibit the promoting effect of ACT on FSH expression by synergizing with INH [3]. Similarly, TGFBβ3 and INHBP/p120 affect the INH/ACT regulatory system by binding to INH and BMP.

Recent studies showed that INH could serve as an important marker for diagnosing male infertility [5] and treating ovarian disorders [6]. In addition, by extracting or synthesizing the recombinant plasmid of the INH subunit fusion protein and INH gene fragment to immunize animals using foreign INH gene therapy, animals can produce INH antibodies to neutralize INH, thus weakening the inhibitory effect of INH on FSH and inducing the pituitary gland to secrete more FSH to promote ovarian development. INH gene therapy can increase the ovulation and reproduction rates of animals, result in the multiparous reproduction of cattle and sheep, and improve the production of poultry eggs [7,8]. This review summarizes the current findings on the structure, function, and mechanism of INH.

留言 (0)

沒有登入
gif