Autoradiographic studies of the mouse Fallopian tube

Cyclic histologic changes in the mouse Fallopian tube corresponding to a specific changing pattern of ³H-thymidine uptake into tubal epithelium suggest a direct correlation between the pattern of nuclear labeling and the cycle-dependent alterations in hormone titers. Human chorionic gonadotropin (HCG)-treated animals showed a peak uptake in reserve cells comparable to that of late proestrus/early estrus. Estradiol-treated animals showed an uptake pattern into secretory cells comparable to the pattern seen in late estrus/metestrus-1. Progesterone-treated animals showed a return to predominantly reserve cell uptake similar to that of the late cycle, metestrus-2/diestrus. These cyclic changes of uptake of ³H-thymidine are interpreted as a growth-maturation-function cycle designed to sustain the egg or zygote in the tube and to replenish the tubal epithelium at the end of a cycle or pregnancy. The intercalary cells are recognized as end-stage elements of predominantly degranulated secretory cells.