Autoradiographic study on localization of progestin target cells in the chicken testes.

Using an autoradiographic technique, the localization and concentration of progestin (P) in cell constituents of testes from the immature 25-to-70-day-old and mature 120-day-old chickens were investigated. After incubation of the frozen tissue sections with 3H-Promegestone (R5020), a synthetic P, specific radioactivity, was found in the seminiferous epithelium and interstitium in all the animals in the presence or in the absence of various non-radioactive steroids, and the intensity of radioactivity differed with age: high in 25-, 70-and 120-day-old chickens, and low in 50-day-old chickens. Estrogen treatment enhanced the intensity of radioactivity in the cells at all ages. The concentration of radioactivity was higher in the seminiferous epithelium than in the interstitial cells. In the frozen tissue sections, it was not possible to identify the kind of cell taking up the high amount of radioactivity. These results indicate that the testes from chicken during their growing stages contain cell constituents that specifically bind P.