Activin and inhibin are two closely related protein complexes that have almost directly opposite biological effects. The activin and inhibin protein complexes are both dimeric in structure, and, in each complex, the two monomers are linked to one another by a single disulfide bond. Activin is composed of two ß subunits, ßA ßA (activin A), ßB ßB (activin B), or ßA ßB (activin AB). Inhibin is composed of an alpha and one of two ß subunits, ßA (inhibin A) or ßB (inhibin B). Activins are produced in many cell types and organs, such as gonads, pituitary gland, and placenta. In the ovarian follicle, activin increases FSH binding and FSH-induced aromatization. It participates in androgen synthesis enhancing LH action in the ovary and testis. In the male, activin enhances spermatogenesis. Also, Activin plays a role in wound repair and skin morphogenesis. Activin is strongly expressed in wounded skin, and overexpression of activin in the epidermis of transgenic mice improves wound healing and enhances scar formation. Activin also regulates the morphogenesis of branching organs such as the prostate, lung, and kidney. There is also evidence showed that lack of activin during development results in neural developmental defects.

Inhibin beta C chain, also known as activin beta-C chain and INHBC, belongs to the TGF-beta family. INHBC forms a homodimeric or heterodimeric through association with alpha and beta subunits, linked by one or more disulfide bonds. Inhibins are heterodimers of one alpha and one beta subunit. Activins are homo- or heterodimers of beta subunits only. Inhibins/activins regulates many physiological processes, such as hypothalamic and pituitary hormone secretion, gonadal hormone secretion, germ cell development and maturation, erythroid differentiation, insulin secretion, nerve cell survival, embryonic axial development or bone growth and so on.

Activin and inhibin are two closely related protein complexes that have almost directly opposite biological effects. The activin and inhibin protein complexes are both dimeric in structure, and, in each complex, the two monomers are linked to one another by a single disulfide bond. Activin is composed of two β subunits, βA βA (activin A), βB βB (activin B), or βA βB (activin AB). Inhibin is composed of an alpha and one of two β subunits, βA (inhibin A) or βB (inhibin B). Activins are produced in many cell types and organs, such as gonads, pituitary gland, and placenta. In the ovarian follicle, activin increases FSH binding and FSH-induced aromatization. It participates in androgen synthesis enhancing LH action in the ovary and testis. In the male, activin enhances spermatogenesis. Also, Activin plays a role in wound repair and skin morphogenesis. Activin is strongly expressed in wounded skin, and overexpression of activin in the epidermis of transgenic mice improves wound healing and enhances scar formation. Activin also regulates the morphogenesis of branching organs such as the prostate, lung, and kidney. There is also evidence showed that lack of activin during development results in neural developmental defects.

Activin and inhibin are two closely related protein complexes that have almost directly opposite biological effects. Activins, members of the TGF-beta superfamily, are disulfide-linked dimeric proteins originally purified from gonadal fluids as proteins that stimulated pituitary follicle stimulating hormone (FSH) release. Inhibins/activins are involved in regulating a number of diverse functions such as hypothalamic and pituitary hormone secretion, gonadal hormone secretion, germ cell development and maturation, erythroid differentiation, insulin secretion, nerve cell survival, embryonic axial development or bone growth, depending on their subunit composition. Activins are homodimers or heterodimers of the various beta subunit isoforms, while inhibins are heterodimers of a unique alpha subunit and one of the various beta subunits.

Inhibins/activins are involved in regulating a number of diverse functions such as hypothalamic and pituitary hormone secretion, gonadal hormone secretion, germ cell development and maturation, erythroid differentiation, insulin secretion, nerve cell survival, embryonic axial development or bone growth, depending on their subunit composition. Inhibins appear to oppose the functions of activins,Inhibins and activins inhibit and activate, respectively, the secretion of follitropin by the pituitary gland.

INHBE (Inhibin Subunit Beta E) is a Protein Coding gene. This gene encodes a member of the TGF-beta (transforming growth factor-beta) superfamily of proteins. The encoded preproprotein is proteolytically processed to generate an inhibin beta subunit. INHBE was identified as a novel putative hepatokine with hepatic gene expression that positively correlated with insulin resistance and body mass index in humans. The quantitative real time-PCR analysis also showed an increase in INHBE gene expression in independent liver samples from insulin-resistant human subjects. INHBE functions as a possible hepatokine to alter the whole-body metabolic status under obese insulin-resistant conditions. Diseases associated with INHBE include Brachydactyly, Type A2, and Liver Benign Neoplasm.

Activin proteins that belong to the transforming growth factor-beta (TGF-β) superfamily, exert their biological actions by binding to heteromeric receptor complexes of type I and type II serine/threonine kinase receptors. On ligand binding, type I and II receptors form a stable complex, resulting in phosphorylation of type I receptors by type II receptors with constitutive kinase activity, and subsequently initiates the activation of downstream molecules including the endogenous Smads. ActRIIB, also known as ActRIIB, is a type II receptor containing an extracellular domain (ECD), a transmembrane segment, and a cytoplasmic region that includes the kinase domain. ActRIIB is a receptor for activin A, activin B and inhibin A. Multiple ActRIIB isoforms can also be generated, which bind activin isoforms with different affinities.