Upregulation of hepatic prolactin receptor gene expression by 17beta-estradiol following trauma-hemorrhage.
Although studies show protective effects of 17beta-estradiol (E2) or prolactin (PRL) treatment in male rats after trauma-hemorrhage (TH), the mechanism of the salutary effects of these agents remains unknown. Because E2 modulates PRL receptor (PRL-R) expression in the liver, we examined whether E2 treatment after T-H has any effects on hepatic PLR-R gene expression. Male Sprague-Dawley rats were subjected to trauma (i.e., 5-cm midline laparotomy) and hemorrhage (35-40 mmHg for 90 min) followed by fluid resuscitation (Ringer lactate) or sham operation and then treated with E2 (50 microg/kg body wt sc) or vehicle immediately before resuscitation. Liver samples were collected at 3 h thereafter, and PRL-R mRNA expression was determined by PCR. Liver expression of PRL-R short-form gene was unaffected by T-H, whereas that of the long-form gene was suppressed. Treatment of T-H rats with E2 significantly increased PRL-R short-form gene expression and normalized PRL-R long-form gene expression to sham levels. In the isolated hepatocytes, PRL-R short-form gene expression was predominant compared with the long-form gene. In contrast, only the short form was detected in Kupffer cells. In vitro treatment by E2 demonstrated an increase in the PRL-R long-form gene in hepatocytes, but E2 had no effect on PRL-R short-form gene expression in either the Kupffer cells or hepatocytes. Thus E2 treatment after T-H in males appears to directly upregulate PRL-R long-form gene expression in hepatocytes. However, the upregulation of the PRL-R short form might involve the interaction of multiple cell types in the liver.
Yokoyama
Yukihiro
Y
Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama 35294-0019, USA.
Kitchens
Williams C
WC
Toth
Balazs
B
Schwacha
Martin G
MG
Bland
Kirby I
KI
Chaudry
Irshad H
IH
D000818:Animals; D002469:Cell Separation; D017931:DNA Primers; D004958:Estradiol / Q000097:blood / Q000494:pharmacology*; D006470:Hemorrhage / Q000378:metabolism*; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D007728:Kupffer Cells / Q000187:drug effects / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D011388:Prolactin / Q000097:blood; D012313:RNA / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D011981:Receptors, Prolactin / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology*; D014947:Wounds and Injuries / Q000378:metabolism*
D017931:DNA Primers; D011981:Receptors, Prolactin; D004958:Estradiol; D012313:RNA; D011388:Prolactin