Nafoxidine-responsive uterine protein: further characterization and distinction from the "estrogen-induced" protein (IP).
In a previous paper, we reported that nafoxidine (UA) stimulated the synthesis of a uterine protein showing the same electrophoretic mobility as the "estrogen-induced protein" (E2-IP) first described by Notides and Gorski. In the present work, we analyzed the IP-containing electrophoretic zone by SDS polyacrylamide-gel electrophoresis, and found that estradiol-17 beta (E2) and nafoxidine stimulated the synthesis of different proteins. As expected, estradiol-17 beta stimulated the synthesis of the E2-IP of 46 000 Mr. On the other hand, UA stimulated the synthesis of 27 000 and 30 000 Mr proteins (UA-IP). These UA-IP were not precipitated by an antiserum raised against E2-IP. Therefore, UA-IP appear to be independent entities and not degradation or precursor products of E2-IP. Both UA-IP are constitutively present in the uterus and even in higher relative amounts in rat brain. The present finding, that an "anti-estrogen", such as nafoxidine, stimulates the synthesis of different proteins than estrogen, provides a new approach to the study of the molecular mechanism of estrogen action.
D000818:Animals; D000918:Antibody Specificity; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D008970:Molecular Weight; D009256:Nafoxidine / Q000494:pharmacology*; D011506:Proteins / Q000032:analysis / Q000276:immunology / Q000302:isolation & purification*; D011759:Pyrrolidines / Q000494:pharmacology*; D051381:Rats; D014599:Uterus / Q000378:metabolism*
D000939:Epitopes; D011506:Proteins; D011759:Pyrrolidines; D009256:Nafoxidine; D004958:Estradiol