SERTOLI CELL FUNCTION DURING INITIATION AND MAINTENANCE OF SPERMATOGENESIS

Abstract

Testicular tubular function has traditionally been judged by morphological criteria. Very recently, we have demonstrated a biochemical marker of Sertoli cell function; the testicular androgen binding protein (ABP). ABP is synthesized in Sertoli cells as a response to FSH stimulation. It disappears completely following hypophysectomy, but reappears after FSH administration. Ho other pituitary hormones are active in stimulating ABP synthesis. ABP is transported with the testicular fluid into the caput epididymis, where it is partly taken up by the lining epithelial cells. We have proposed that ABP serves as an important store of androgenic hormones (mainly testosterone and dihydrotestosterone) that are necessary for initiation and maintenance of spermatogenesis. ABP was found to be present at low concentrations in testes of prepubertal rats, but increased rapidly during sexual maturation. Experimental cryptorchidism dramatically decreased the testicular and epididymal content of ABP demonstrating an impaired Sertoli cell function under these experimental conditions. The finding indicates that Sertoli cell damage may be an important factor in the overall impairment of spermatogenesis found in this condition.