TY - JOUR
T1 - Reduced Expression of Immunoreactive β2-Adrenergic Receptor Protein in Human Myometrium with Labor
AU - Chanrachakul, Boonsri
AU - Matharoo-Ball, Balwir
AU - Turner, Anita
AU - Robinson, Graham
AU - Broughton-Pipkin, Fiona
AU - Arulkumaran, Sabaratnam
AU - Khan, Raheela N.
PY - 2003/10
Y1 - 2003/10
N2 - A considerable body of evidence exists suggesting that the β 2-adrenergic receptor (β2-AR) mediates uterine relaxation. However, little information exists on the localization, distribution, or expression of β2-ARs in the human myometrium during the nonpregnant to labor transition. We have used immunochemical methods to investigate β2-AR localization and expression in the nonpregnant, term pregnant, and term parturient uterus. Myometrial biopsies were obtained from 1) nonpregnant, menstruating women undergoing hysterectomy; 2) singleton term pregnant women undergoing elective cesarean section before the onset of labor; or 3) singleton term pregnant women undergoing emergency cesarean section after spontaneous labor. Tissues were processed for immunohistochemistry, immunofluorescence, and Western blotting and a primary polyclonal antibody specific to the human β2-AR to identify immunoreactive myometrial β2-AR. Protein levels were subsequently quantified by densitometry relative to rat brain protein. Immunohistochemistry and immunofluorescence demonstrated the presence of β2-AR predominantly at the plasma membrane and also in the cytosol of myometrial cells. A 2-fold decrease in protein levels of the β2-AR was apparent in the myometrium of labor compared with that of nonpregnant and pregnant nonlaboring women (P < 0.05). These results demonstrate that down-regulation of β2-AR protein with labor may constitute a contributory mechanism by which uterine quiescence is removed at term.
AB - A considerable body of evidence exists suggesting that the β 2-adrenergic receptor (β2-AR) mediates uterine relaxation. However, little information exists on the localization, distribution, or expression of β2-ARs in the human myometrium during the nonpregnant to labor transition. We have used immunochemical methods to investigate β2-AR localization and expression in the nonpregnant, term pregnant, and term parturient uterus. Myometrial biopsies were obtained from 1) nonpregnant, menstruating women undergoing hysterectomy; 2) singleton term pregnant women undergoing elective cesarean section before the onset of labor; or 3) singleton term pregnant women undergoing emergency cesarean section after spontaneous labor. Tissues were processed for immunohistochemistry, immunofluorescence, and Western blotting and a primary polyclonal antibody specific to the human β2-AR to identify immunoreactive myometrial β2-AR. Protein levels were subsequently quantified by densitometry relative to rat brain protein. Immunohistochemistry and immunofluorescence demonstrated the presence of β2-AR predominantly at the plasma membrane and also in the cytosol of myometrial cells. A 2-fold decrease in protein levels of the β2-AR was apparent in the myometrium of labor compared with that of nonpregnant and pregnant nonlaboring women (P < 0.05). These results demonstrate that down-regulation of β2-AR protein with labor may constitute a contributory mechanism by which uterine quiescence is removed at term.
UR - http://www.scopus.com/inward/record.url?scp=0242288649&partnerID=8YFLogxK
U2 - 10.1210/jc.2003-030692
DO - 10.1210/jc.2003-030692
M3 - Article
C2 - 14557486
AN - SCOPUS:0242288649
SN - 0021-972X
VL - 88
SP - 4997
EP - 5001
JO - Journal of Clinical Endocrinology and Metabolism
JF - Journal of Clinical Endocrinology and Metabolism
IS - 10
ER -