Androgen binding protein is secreted by:

Seoli cells REF: Ganong 22nd edition, chapter-23, http://en.wikipedia.org/wiki/Androgen-binding_protein 'The Seoli cells secrete androgen-binding protein (ABP), inhibin, and MIS" Androgen-binding protein (ABP) is a glycoprotein (beta-globulin) produced by the Seoli cells in the seminiferous tubules of testis that binds specifically to testosterone (T), dihydrotestosterone (DHT), and 17-beta-estradiol. 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's production is regulated under influence of FSH on Seoli cell, enhanced by insulin, retinol, and testosterone. ABP may also be secreted in other organs; for instance, mice produce a salivary ABP