Proceedings of The Physiological Society
University of Manchester (2010) Proc Physiol Soc 19, PC284
Hepatic CFTR mRNA expression under obstructive cholestasis condition in female rats with hyperprolactinemia: comparison with mRNA expression of short and long prolactin receptor isoforms
N. Kushnareva1, O. V. Smirnova2
1. Biological Department, Moscow State University, Moscow, Russian Federation. 2. Biological Department, Moscow State University, Moscow, Russian Federation.
Female prevalence of obstructive cholestasis (OC) development has been established and assumed to be related particularly to high level of prolactin in serum of normal and especially pregnant women and abundance of prolactin receptors (PrlR) in their liver. Our aims was to investigate prolactin influence on cholangiocyte CFTR (cystic fibrosis transmembrane conductance regulator) mRNA expression using rat model of hyperprolactinemia combined with OC in the relation to the alterations of mRNA level and ratio of short and long PrlR isoforms in these cell types. Hyperprolactinemia was induced by donor pituitary transplantation under kidney capsule of recipient. Briefly, during diethylether anesthesia, a 1.0-cm paracostal incision was made to expose the left kidney, which was then covered with a warm sterile 0.9% NaCl-soaked gauze ready for transplantation. One anesthetized donor (female rat) was then humanely decapitated to remove the pituitary gland. The gland from the donor was inserted into the prepared renal capsule of the recipient. Sham operation consisted of exposure of the left kidney and gentle touch of the renal fascia with forceps. OC was induced by common bile duct ligation, under diethyl ether anesthesia, for 14 days. Cholangiocytes were isolated from female rat liver. Expression level and mRNA ratio of short and long PrlR isoforms, mRNA of CFTR in cholangiocytes were tested by real-time PCR using 3 housekeeping genes and normalized on hprt expression. Persistent hyperprolactinemia combined with OC led to sharp decrease of bile bilirubin level, appearance of “limy bile” and absence of bile flow restoration after decompression. In cholangiocytes of these animals only short PrlR isoform mRNA was increased resulted in elevation of short to long isoform mRNA ratio. OC combined with hyperprolactinemia caused sharp 3-folds elevation of CFTR mRNA expression in cholangiocytes as compared with OC. Hyperprolactinemia without bile duct obstruction had no marked influence on CFTR mRNA expression. Its seems that in cholangiocytes short PrlR isoform mRNA elevated under OC condition as was shown by us early, and additionally increased by hyperprolactinemia might play principal role in positive regulation of CFTR mRNA expression under OC condition. It is concluded that pseudopregnancy induced by hyperprolactinemia elevates CFTR mRNA expression and may contribute to changes of bile composition and difficulties in bile flow restoration observed in this model. Supported by RFBR (grant 07-04-00319-a).
Where applicable, experiments conform with Society ethical requirements