J. Biol. Chem., Vol. 263, Issue 7, 3261-3265, Mar, 1988
Persistent estrogen induction of hepatic Xenopus laevis serum retinol binding protein mRNA
DM McKearin and DJ Shapiro
Department of Biochemistry, University of Illinois, Urbana 61801.
Administration of estradiol-17 beta to male Xenopus laevis induces the
hepatic mRNA coding for the serum retinol binding protein (RBP)
approximately 10-fold, both in vivo and in primary liver cultures. Estrogen
induction of RBP mRNA is completely blocked by the anti- estrogen,
hydroxytamoxifen. Testosterone administration reduces the elevated level of
RBP mRNA observed in livers of female X. laevis to the constitutive level
seen in livers of control male animals, and partially blocks the estrogen
induction of RBP mRNA. Intracellular RBP mRNA levels therefore represent a
balance between the opposing effects of estradiol-17 beta and testosterone.
In marked contrast to the estrogen induction of vitellogenin mRNA, which
requires the continuous presence of exogenous estrogen, induction of RBP
mRNA persists for at least 4 months after a single injection of estrogen.
Runoff transcription measurements demonstrate that persistent induction of
RBP mRNA is due to an increased rate of RBP gene transcription.
Administration of hydroxytamoxifen abolishes persistent induction of RBP
mRNA, suggesting that residual hormone receptor complex plays a role in the
persistent induction of RBP gene transcription. The persistent estrogen
induction of RBP mRNA provides the first demonstration of long-term
activation of the transcription of a hormone- responsive gene in response
to a transient dose of a steroid hormone.