Effects of perinatal estrogen on mouse mammary response to corticoids in vitro.

Effects of three adrenal corticoids on in vitro mammary differentiation were compared in neonatally estrogenized (E) and uninjected control (N) BALB/c Crgl female mice. E mice were injected with 10 microgram of 17 beta-estradiol on each of the first 5 days of life. At 4 weeks of age, all mice were pretreated with 1 microgram 17beta-estradiol and 1 mg progesterone for 9 consecutive days. Groups of 10 or more entire mammary glands then were organ-cultured for 5 days at 37 degree C on chemically defined medium in 95% O2/5% CO2 with various combinations of hormones: mammotropin (M), somatotropin (S), insulin (I), thyroxine (T); and corticosterone (B), aldosterone (A), or cortisol (F). Differentiation followed a quantitative pattern of MSIT less than BMSIT less than AMSIT less than FMSIT for both E and N tissues. E tissues formed more alveoli and more lobules in vitro than N tissues with each of the corticoids tested. These findings may have pathologic significance.