Androgen binding protein is secreted by the following structure:

Seoli cell functions include, Physical suppo for the spermatogenic cells Nutritional regulation of the developing spermatozoa Protection from autoimmune attack by immunoglobulins in the blood Phagocytosis of residual bodies shed by the maturing spermatozoa Secretion of fluid for sperm transpo, including androgen-binding protein (ABP), which combines with the testosterone produced by interstitial cells and is released into the tubule lumen (ABP secretion increases in response to increased levels of FSH and testosterone), and inhibin, which acts on the pituitary to decrease FSH production Seoli cells also may secrete estrogen Ref: Paulsen D.F. (2010). Chapter 22. Male Reproductive System. In D.F. Paulsen (Ed), Histology & Cell Biology: Examination & Board Review, 5e.