Age-dependent change in sensitivity of oestrogen-induced uterine cell proliferation of mice, estimated by incorporation of [125I]iododeoxyuridine.
The stimulative effects of both oestradiol-17 beta (E2) and diethylstilbestrol (DES) injections on the proliferation of uterine cells of mice were investigated by using 5-[125I]iodo-2'-deoxyuridine [( 125I]IdUrd) incorporation as an index. Female mice of (WB X C57BL/6)F1 were neonatally castrated, and the [125I]IdUrd uptake by the whole uterus was determined on days 1, 5, 10, 20, 30 and 40 after birth. The relative minimal dose (a minimal dose expressed per body weight, microgram/g b.wt) of E2 necessary for the maximal [125I]IdUrd uptake was much higher than the relative minimal dose of DES on days 1, 5, and 10, when the serum concentration of alpha-fetoprotein was relatively high. However, the relative minimal dose of E2 was comparable to that of DES on days 30 and 40, when the concentration of alpha-fetoprotein was negligible. The difference between the effect of injected E2 and DES during neonatal and suckling periods seems to be attributable to the presence of alpha-fetoprotein in serum, which binds to E2 but not to DES with high affinity. When the relative minimal dose of DES necessary for the maximal [125I]IdUrd uptake was examined in detail, the value was lower on days 10 and 20 of age than on days 30 and 40 of age. This might represent the increased sensitivity of uterine cells to oestrogen on days 10 and 20.
N
N
Terada
T
T
Yamane
Y
Y
Ogasawara
K
K
Matsumoto
Y
Y
Kitamura
D000375:Aging; D000818:Animals; D000831:Animals, Newborn; D002455:Cell Division / Q000187:drug effects; D004054:Diethylstilbestrol / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D007065:Idoxuridine; D066298:In Vitro Techniques; D051379:Mice; D010052:Ovariectomy; D014599:Uterus / Q000166:cytology / Q000187:drug effects*; D000509:alpha-Fetoproteins / Q000378:metabolism
D004967:Estrogens; D000509:alpha-Fetoproteins; D004958:Estradiol; D004054:Diethylstilbestrol; D007065:Idoxuridine