Estrogen and progesterone differentially regulate carbonic anhydrase II, III, IX, XII, and XIII in ovariectomized rat uteri

Changes in the uterus expression of carbonic anhydrase (CA) II, III, IX, XII, and XIII were investigated under the influence of sex-steroids in order to elucidate mechanisms underlying differential effects of these hormones on uterine pH. Uteri of ovariectomised rats receiving over three days either vehicle, estrogen, or progesterone or three days estrogen followed by three days either vehicle or progesterone were harvested. Messenger RNA (mRNA) and protein levels were quantified by real-time PCR and Western blotting, respectively. The distribution of CA isoenzymes proteins were examined by immunohistochemistry. The levels of CAII, III, XII, and XIII mRNAs and proteins were elevated while levels of CAIX mRNA and protein were reduced following progesterone-only and estrogen plus progesterone treatment, compared to the control and estrogen plus vehicle, respectively. Following estrogen treatment, expression of CAII, IX, XII, and CAXIII mRNAs and proteins were reduced, but remained at a level higher than control, except for CAIX, where its level was higher than the control and following progesterone treatment. Under progesterone-only and estrogen plus progesterone influences, high levels of CAII, III, XII, and XIII were observed in uterine lumenal and glandular epithelia and myometrium. However, a high level of CAIX was observed only under the influence of estrogen at the similar locations. In conclusion, high expression of CAII, III, XII, and XIII under the influence of progesterone and estrogen plus progesterone could result in the reduction of uterine tissue and fluid pH; however, the significance of high levels of CAIX expression under the influence of estrogen remains unclear.