Comparison of trophinin, tastin, and bystin proteins in explants of intact fallopian tube with or without incubation with hCG. Explants were cultured for 24 hours without hCG (A–D) or with 100 IU/ml hCG (E–H), and were immunostained for trophinin (A, E), tastin (B, F), bystin (C, G), and second antibody alone (D, H). All photographs presented are in the same magnification, and the bar in (H) indicates 50 μm. (te, tubal epithelia).