Estrogen-induced changes in the maltase activity of rat uterus

The effect of estrogen administration on uterine maltase activities at pH 4.3, 5.6 and 6.2 have been studied in the ovarleotomized immature rat. Estradiol (in total doses of 0.5, 1.0 and 2.0 /ug) for 3 consecutive days resulted in increased uterine maltase levels at pH 4.3 and pH 5.6, though the activity at pH 6.3 remained unchanged. A single injection of 2/ug estradiol resulted in an increase in the enzyme activities at pH 4.3 and pH 5.6; this was detectable in 36 hours and reached peak levels 48 hours after the hormone injection. Actinomycin and cycloheximide blocked the estradiol-induced increase in the enzyme activities. Pretreatment with clomiphene also neutralized estradiol-induced increases in the enzyme activities.