ESTROGEN-RECEPTOR-ALPHA AND ESTROGEN-RECEPTOR-BETA EXPRESSION IN UPPER GASTROINTESTINAL-TRACT WITH REGULATION OF TREFOIL FACTOR FAMILY 2 MESSENGER-RNA LEVELS IN OVARIECTOMIZED RATS

This study compared expression of two estrogen receptor (ER alpha and ER beta) genes in the rat upper gastrointestinal tract and the effects of 17 beta-estradiol administration on gastric trefoil factor family (TFF) mRNA steady-state levels in ovariectomized rats. Estrogen recept or alpha and beta cDNA fragments from fundic mucosa were cloned by rev erse transcriptase polymerase chain reaction (RT-PCR) and sequenced. B oth ER subtypes were detected in fundus, antrum and duodenum by RT-PCR . Northern analysis of poly(A)(+) mRNA hom fundic mucosa showed that E R alpha mRNA is expressed as a single transcript at 6.5 kb and ER beta is expressed as multiple transcripts with major transcripts ranging f rom 1.1-4.7 kb. ER beta mRNA was expressed in greater abundance than E R alpha mRNA. Fundic TFF2 mRNA steady-state levels were increased by 1 7 beta-estradiol administration in ovariectomized rats with no signifi cant change in TFF1 mRNA levels. These studies show expression of both ER subtypes in the rat upper gastrointestinal tract with regulation o f TFF2 mRNA by 17 beta-estradiol. These results suggest that estrogens , probably acting via ER beta, have a direct role in regulating gastri c physiology. (C) 1997 Academic Press.