Androgen-binding protein

Androgen-binding protein (ABP) is a glycoprotein (beta-globulin) produced by the Sertoli cells[1] in the seminiferous tubules[2] of the testis that binds specifically to testosterone (T), dihydrotestosterone (DHT), and 17-beta-estradiol.

Androgen-binding protein, Sex hormone-binding globulin
Identifiers
Symbol	SHBG
Alt. symbols	ABP
NCBI gene	6462
HGNC	10839
OMIM	182205
RefSeq	NM_001040
UniProt	P04278
Other data
Locus	Chr. 17 p13-p12

Because ABP binds to T and DHT, these hormones are made less lipophilic and become concentrated within the luminal fluid of the seminiferous tubules. The higher levels of these hormones enable spermatogenesis in the seminiferous tubules and sperm maturation in the epididymis.

ABP has the same amino acid sequence as sex hormone-binding globulin (SHBG); the difference is the site of production and the addition of different sugar moieties. ABP contains 403 amino acids, resulting in a molecular weight of 44,533. Its gene is located on chromosome 17.

ABP’s production is regulated under the influence of FSH[2] on Sertoli cells, enhanced by insulin, retinol, and testosterone.

ABP may also be secreted in other organs; for instance, mice produce a salivary ABP.

See also

• Sex hormone-binding globulin (SHBG)

References

1. Bardin CW, Musto N, Gunsalus G, Kotite N, Cheng SL, Larrea F, Becker R (1981). "Extracellular androgen binding proteins". Annual Review of Physiology. 43: 189–98. doi:10.1146/annurev.ph.43.030181.001201. PMID 7011179.
2. Hansson V, Weddington SC, French FS, McLean W, Smith A, Nayfeh SN, Ritzén EM, Hagenäs L (September 1976). "Secretion and role of androgen-binding proteins in the testis and epididymis". Journal of Reproduction and Fertility. Supplement (24 suppl): 17–33. PMID 1069850.

External links

• Androgen-Binding+Protein at the US National Library of Medicine Medical Subject Headings (MeSH)
• Ensembl Gene ref Protein ref