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Placental hormone that reaches maximum levels in maternal serum during labor; helps to regulate production of gonadotropin-releasing hormones, human chorionic gonadotropin, and steroids by the placenta.
[active + -in]
activin/ac·ti·vin/ (ak´tĭ-vin) a nonsteroidal regulator synthesized in the pituitary glands and gonads that stimulates the secretion of follicle-stimulating hormone.
A polypeptide growth factor that is synthesized in the pituitary gland and the gonads and stimulates the secretion of follicle-stimulating hormone.
ActivinEither of two dimeric proteins belonging to the TGF-beta superfamily (as do inhibin and bone morphogenic protein) which act primarily through SMADs, a class of signal transducers, which are involved in DNA-binding and signal transduction. Activins are involved in all stages of the cell cycle: proliferation, differentiation, metabolism, homeostasis, and death (apoptosis), as well as immune response and tissue repair—activins A and B are highly expressed during wound repair and healing, and have yin-yang relationship with inhibin. Activins are involved in differentiation of erythroid precursors and erythroleukemia cell lines, neuronal survival, stimulation of insulin and anterior pituitary hormone secretion, regulation of the menstrual cycle, increasing FSH production and granulosa cell differentiation by binding to follistatin, an FSH release inhibitor.
Placental hormone that reaches maximum levels in maternal serum during labor.
a gonadal peptide hormone isolated from follicular fluid; has an unidentified role in stimulating FSH secretion.