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 (ăk′tə-vĭn, ăk-tĭv′ĭn)
A polypeptide growth factor that is synthesized in the pituitary gland and the gonads and stimulates the secretion of follicle-stimulating hormone.

[activ(ate) + (inhib)in (from its activating follicle-stimulating hormone).]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
References in periodicals archive ?
Of the proteins the researchers examined, the pattern of two proteins, Activin A and follistatin, stood out from the rest.
First, they increased the levels of Activin A in the cochleas of normal mice.
Genetic studies in familial PAH (fPAH) and idiopathic PAH (iPAH) have discovered that transforming growth factor-[sz] (TGF-[sz]) superfamily plays an important role, and the identified mutations occur inbone morphogenetic protein type 2 receptor( BMPR2 ), activin receptor-like kinase type 1 ( ALK1 ), Endoglin , and SMAD9.
Increased number of embryos in synthetic inhibin treated (SI) and SFBFF antiserum treated (AI) group ewes shown in the present study, could be attributed to the stimulatory effect of inhibin or its immunoneutralization on the ovary, either through an endocrine effect by the suppressing inhibitory action of inhibin and stimulatory action of activin on ovarian gonadotrophs, and subsequently FSH secretion.
M2 PHARMA-July 27, 2018-Tolero Doses First Patient in Phase 1 Study of Activin A Receptor Type 1 Inhibitor in Advanced Solid Tumors
SB-431542 is a potent and specific inhibitor of transforming growth factor-beta superfamily type I activin receptor-like kinase (ALK) receptors ALK4, ALK5, and ALK7.
The tumor cells were focally positive for desmin [Figure 3] and negative for CD117, CD34, DOG-1, and activin receptor-like kinase (ALK-1) protein.
Moreover, the 1, 2, 4, 5 tetrasubstituted imidazole derivatives are strong inhibitors of thromboxane A2 synthase and also hold back against p38 MAP kinase, cyclooxygenase-2 (COX-2) and (TGF-b1) type 1 activin receptor like kinase (ALK5) (Nikalje et al., 2015).
The team found that the Wnt pathway loads up the cellular machinery to begin copying and activating genes, and then the Activin pathway ramps up that activity many fold.
In addition to the ubiquitously expressed T[beta]Rs (T[beta]RII and ALK5), the activin receptor-like kinase-1 (ALK1) has more distinct expression properties as it is preferentially expressed on proliferating vascular endothelial cells; thus inhibition of ALK1 might block tumor-induced angiogenesis.
These pluripotent stem cells show primed characteristics and are highly dependent upon the activation of FGF and activin signalling pathways for their self-renewal [20, 21].
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