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inhibin
So named for its property of inhibiting FSH secretion. Member of superfamily of proteins that includes TGF-beta, mullerian inhibitory factor, & activins.
Function:
Inhibins & activins inhibit & activate, respectively, secretion of follitropin by the pituitary gland.
they are involved in regulating diverse functions, including:
- hypothalamic hormone secretion
- pituitary hormone secretion
- gonadal hormone secretion
- germ cell development & maturation
- erythroid differentiation
- insulin secretion
- nerve cell survival
- embryonic axial development or bone growth dependent on subunit composition
Inhibins oppose the functions of activins.
Structure:
- Inhibins are heterodimers of one alpha & one beta subunit
- Activins are homo- or heterodimers of beta subunits only
Laboratory:
- inhibin antigen in tissue
Specific
inhibin-A
inhibin-B
General
glycoprotein
multisubunit protein
secreted protein
Properties
COMPARTMENT: extracellular compartment
SECRETED-BY: granulosa cell
WITHIN: ovary
sertoli cell
WITHIN: testis
unspecified cell type
WITHIN: placenta
SUBUNITS: inhibin alpha chain
MOTIF: signal sequence {1-18}
peptide motif {61-62}
N-glycosylation site {N146}
peptide motif {232-233}
cysteine residue {C262}
MODIFICATION: cysteine residue {C328}
N-glycosylation site {N268}
cysteine residue {C291}
MODIFICATION: cysteine residue {C363}
cysteine residue {C295}
MODIFICATION: cysteine residue {C365}
N-glycosylation site {N302}
cysteine residue {C327}
MODIFICATION: cysteine residue {C-INTERCHAIN}
cysteine residue {C328}
MODIFICATION: cysteine residue {C262}
cysteine residue {C363}
MODIFICATION: cysteine residue {C291}
cysteine residue {C365}
MODIFICATION: cysteine residue {C295}
beta-inhibin
MOTIF: glycosylation site
cysteine-rich region
MOTIF: cysteine residue {X+0}
MODIFICATION: cysteine residue {X+7}
cysteine residue {X+6}
MODIFICATION: cysteine residue {X+50}
cysteine residue {X+7}
MODIFICATION: cysteine residue {X+0}
cysteine residue {X+26}
MODIFICATION: cysteine residue {X+70}
cysteine residue {X+29}
MODIFICATION: cysteine residue {X+72}
cysteine residue {X+49}
MODIFICATION: cysteine residue {X+49}
cysteine residue {X+50}
MODIFICATION: cysteine residue {X+6}
cysteine residue {X+70}
MODIFICATION: cysteine residue {X+26}
cysteine residue {X+72}
MODIFICATION: cysteine residue {X+29}
References
- Williams Textbook of Endocrinology, 8th ed, JD Wilson
& DW Foster (eds), WB Saunders Co, Philadelphia PA,
1992, pg 983
- Matzuk et al
Alpha-inhibin is a tumour-suppressor gene with gonadal
specificity in mice.
Nature 360:313 1992
PMID: 1448148
- Medical Knowledge Self Assessment Program (MKSAP) 11, American
College of Physicians, Philadelphia 1998
Components
beta-inhibin or activin beta chain
inhibin alpha chain (INHA)