We studied the in-vitro secretory function of non-polarized and polarized cultured Fallopian tube epithelial cells by measurement of the placental protein 14 (PP14) secretion in primary cultures and subcultures from Fallopian tubes obtained from eight premenopausal women in different phases of the ovarian cycle. Primary cultures were established in minimal essential medium in Earle's salts supplemented with fetal bovine serum and the cells were subcultured for six passages, in the polarized cell cultures, the cells being seeded on an extracellular matrix system. Cell freezing was carried out using 10% dimethyl sulphoxide. PP14 secretion into the culture media was measured by a radioimmunoassay using I-125-PP14 as label and rabbit anti-human PP14 serum. There was a large amount of PP14 secretion into the culture media in primary cultures, the secretion decreasing considerably after subculture 1. PP14 secretion after subculture 2 was not different from the control values. Polarized and non-polarized cells secreted similar amounts of PP14 and frozen-thawed cells did not appear to secrete PP14. Epithelial cells from Fallopian tubes obtained at different phases of the ovarian cycle did not appear to show any difference in PP14 secretion rates. Our data suggest that the in-vitro secretion of PP14 by human Fallopian tube epithelial cells is adversely affected by cell ageing and freezing.