Hormonal response of human breast tissue in organ culture

Several studies have shown the importance of various hormones in the proliferation of normal epithelial cells. The purpose of this work was to analyze the effects of estrogen and/or progesterone, in the presence of insulin and hydrocortisone on DNA-labeling index (DNA-LI) and mitotic index (MI) of normal human breast tissue in organ cultures. Twelve normal breast samples were individually cultured and subjected to 5 different culture conditions: Group I contained only Medium 199 and explants were cultured for one hour. Group II contained 5.0 μg/ml insulin (I) and 1.0 μg/ml hydrocortisone (Hc). Group III contained I, Hc and 0.05 μg/ml 17 β-estradiol (E). Group IV contained I, Hc and 1.0 μg/ml progesterone (Prog). Group V contained I, Hc, E and Prog. Groups II-V were cultured for 5 days. Results indicated that there was a significant increase in cell proliferation in the presence of any combination of hormones as indicated by the DNA-LI (P < 0.0001) and MI (P < 0.0005) from Group II through V versus Group I. There was also a significant increase (P < 0.0001) in DNA-LI in the presence of I, Hc and E (Group III) in comparison with groups containing I and HC (Group II), I, Hc and Prog (Group IV) and I, Hc, E and Prog (Group V). There was no significant differences in DNA-LI and MI among other groups that were cultured for 5 days. Thus, these results indicate that ovarian hormones, mainly estrogen, have a stimulatory effect upon normal breast tissue, however, this effect is inhibited by progesterone.