Ovarian Hormones Regulate SP ‐D Expression in the Mouse Uterus During Estrous Cycle and Early Pregnancy

PROBLEM: Differential expression of SP-D in the cycling human and mouse endometrium suggests its regulation by ovarian hormones. METHOD OF STUDY: SP-D expression in the mouse uterus was analyzed across the estrous cycle and during early pregnancy. Effect of exogenous ovarian hormones on the uterine expression of SP-D was analyzed. RESULTS: SP-D expression varied across the estrous cycle and peaked in the estrous phase. SP-D transcript levels increased by fourfold in the uteri of estrogen-treated mice while co-administration of estrogen and progesterone enhanced SP-D levels by ninefold. However, treatment with progesterone alone significantly downregulated SP-D expression. Diethylstilbestrol enhanced SP-D transcript levels in the uteri of immature mice by 10-fold. During pregnancy, SP-D levels declined rapidly from 0.5 dpc to 6.5 dpc. In silico analysis predicted the presence of two potential ERE and 1 PRE in the mouse SP-D gene promoter region. CONCLUSION: Estrogen positively regulates expression of SP-D in the mouse uterus. Progesterone, along with estrogen synergizes SP-D expression, however, when administered alone results in negative regulation.