AJP - Endocrinology and Metabolism, Vol 242, Issue 2 121-E126, Copyright © 1982 by American Physiological Society
Theophylline-estrogen interaction in the rat uterus: role of the ovary
J. Steinsapir, A. M. Rojas and A. Tchernitchin
Uterine edema induced by 0.1 microgram/100 g body wt of estradiol further
increases in the presence of theophylline. Theophylline alone or in the
presence of 0.001, 0.01, 0.1, and 1 microgram/100 g body wt of estradiol
increases uterine RNA and protein content 6 h after its administration, as
compared with the same doses of estradiol alone. Both phenomena disappear
in the ovariectomized immature rat, suggesting that theophylline
potentiates the action of gonadotropins, increasing the synthesis of
endogenous ovarian estrogens by the immature ovary. Theophylline decreases
the number of eosinophils in the blood and concurrently decreases
estrogen-induced uterine eosinophilia at doses of 0.01, 0.1, 1, 10, and 30
micrograms/100 g body wt of estradiol. Estrogen binding by uterine
eosinophils in vitro increases in the presence of theophylline. This effect
of theophylline could also explain the increase in vivo in estrogen-induced
uterine edema.
