Conversion of Proliferative Endometrium to Secretory Endometrium by Progesterone in Organ Culture

SUMMARY Human proliferative endometrial tissue was maintained in organ culture. Glandular cells in the fragments were stimulated to secrete by adding progesterone to the culture medium—but not by insulin, oestradiol or cortisol; insulin enhanced the effect of progesterone. With progesterone, subnuclear vacuolation appeared in the glandular cells after 2–3 days. As the culture continued, these vacuoles disappeared and secretion into the lumen occurred.