Y. Ninomiya et al., VITAMIN-A IS INVOLVED IN ESTROGEN-INDUCED CELL-PROLIFERATION BUT NOT IN CYTODIFFERENTIATION OF THE CHICKEN OVIDUCT, Journal of Endocrinology, 148(2), 1996, pp. 257-265
We examined vitamin A-deficient chicks to determine whether vitamin A
affects the estrogen-induced development of the chick oviduct. When ov
iduct development was stimulated for 5 days with the synthetic estroge
n, diethylstilbestrol, the wet weight of the oviduct in vitamin A-defi
cient chicks was only half that in control chicks. The DNA content in
this tissue showed that the decreased oviduct weight in the vitamin A-
deficient chicks was caused by the decreased proliferation of oviduct
cells. However, the estrogen-induced expression of the ovalbumin gene
was not affected by the vitamin A deficiency, suggesting that estrogen
-induced cytodifferentiation is not affected by vitamin A. To clarify
the vitamin A action on estrogen-induced development in the oviduct, t
ranscripts of nuclear estrogen receptor (ER) and all-trans-retinoic ac
id (RAR alpha, beta and gamma) receptors, which exert the effects of e
strogen and vitamin A, were measured. The ER, RAR alpha: and RAR beta
genes, but not that of RAR gamma, were expressed during oviduct develo
pment, indicating that estrogen and vitamin A may control the expressi
on of target genes through their cognate receptors. Thus, we have show
n that vitamin A is involved in estrogen-induced cell proliferation bu
t not in cytodifferentiation of the chicken oviduct.