Antagonistic effect of the antiestrogen 4-hydroxytamoxifen on estradiol-stimulated acetylation of nuclear high mobility group (HMG) proteins in the uterus of newborn guinea-pigs.

The effect of the antiestrogen 4-hydroxytamoxifen on the estradiol-stimulated acetylation of nuclear high mobility group (HMG) proteins was studied in the uterus of newborn (3-day-old) guinea-pig. 4-Hydroxytamoxifen (10(-6) M) selectively inhibits the stimulatory effect of estradiol (5 x 10(-8) M) on the acetylation of HMG-14 proteins 30 min after incubation with uterine tissue slices. No effect of 4-hydroxytamoxifen was observed on HMG-1 + HMG-2 or HMG-17 proteins. The data suggest that the blockage of HMG-14 acetylation is an early event in gene expression which is in relation to the antagonistic effect of the antiestrogen.