Inhibins and Activins

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Hello bloggers,
The last blog of mine will be regarding Inhibins and Activins.
These Inhibins are the growth factors which are synthesized in the gonads.
They are members of TGF family of proteins.
Function: They show their effect directly on gonadal and extragonadal tissue. Apart from targeting the pituitary gland they also play a role as paracrine/autocrine regulators of gonadal function
They induce responses in tissues other than gonads.
Chemical nature:
* Inhibins are heterodimer with alpha and beta polypeptide subunits and Activins are dimmers with only beta subunits .
* A mature form of subunit has 134 amino acids.
Inhibins and Activins are named along with the polypeptide composition as
Inhibin A(alpha and beta A),
Inhibin B(alpha and beta B),
Activin A(2 beta A units),
Activin AB ( beta A and Beta B).

The important thing is that these gonadal derived proteins are capable of either inhibiting (Inhibins) or stimulating (Activins) the pituitary FSH production.
Site of synthesis: The major gonadal sites of Inhibin synthesis are Sertoli cells in males and granulose cells in females.
In adults Inhibins are also synthesized in adrenal glands, spleen and nervous system.

Recent studies were done in which mice with Inhibin deficiency was studied. These mice in which Inhibin gene was missing developed normally but finally showed gonadal stromal tumors.
Reference: http://ebm.rsmjournals.com/content/231/5/534.long dated December 1, 2011.

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Siva Mavuduru's picture

Hi Sravani what are activins chemically? where are they synthesized? do they resemble the inhibins? do these function directly or by acting on the pituitary?
Sravani kompella's picture

1.Inhibins are proteins consisting of alpha and beta subunits linked by disulfide bridges.Each form of inhibin has a common alpha-subunit, but a highly distinct beta-subunit. The beta-subunits and the alpha-subunit are linked to form inhibins A and B which exert an inhibitory effect on basal FSH secretion The dimer formed by either two beta A-subunits or two distinct beta A- and two beta B-subunits are activins and possess FSH-stimulating activity. Inhibin and activin are chemically related and the chemical forms of inhibin, activin are produced by human placenta. http://www.ncbi.nlm.nih.gov/pubmed/3122219 referered on 7th december 2011 http://www.ncbi.nlm.nih.gov/pubmed/9032804 referered on 7th december 2011
Siriki Praveen Kumar's picture

clear regarding inhibins,... how about those of activins??

Regards,

S. Praveen Kumar.

sirikipraveen11@gmail.com

Pharma warriors

Sravani kompella's picture

Hello praveen, Both inhibins and activins have everthing similar but they act as antagonist to each other...
Sandhya Sravya malla's picture

good blog and nicely explained!!! m.sandhyasravya@gmail.com
Sravani kompella's picture

Hello sravya, Thank you very much

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