Effects of 17 beta-estradiol and progesterone on mitogen-activated protein kinase expression and activity in rat uterine smooth muscle.
Activation of mitogen-activated protein kinases (MAPKs) is a critical event in mitogenic signal transduction. MAPKs are activated by tyrosine phosphorylation and translocate to different cellular compartments affecting protein function and gene expression. MAPK expression and activity was examined in uterine smooth muscle from rats pretreated with estradiol-17 beta alone or with estradiol-17 beta and progesterone. MAPK expression was detected by immunoblotting using erk1/2 antibodies. MAPK activity was detected by measurement of the phosphorylation of a MAPK-specific peptide sequence of myelin basic protein. Steroid treatment caused a modest (20%) decline in erk 1 and 2 expression in membrane and cytosolic fractions. Both estrogen and progesterone increased MAPK tyrosine phosphorylation and membrane-associated MAPK activity. Steroid treatment increased cytosolic MAPK tyrosine phosphorylation, but not enzymatic activity. These data suggest that gonadal steroid hormones, which stimulate uterine hypertrophy, may exert their hypertrophic effects by increasing MAPK activity.
Ruzycky
A L
AL
Magee Womens Research Institute, University of Pittsburgh, PA 15213, USA.
D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D004359:Drug Therapy, Combination; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D009130:Muscle, Smooth / Q000187:drug effects* / Q000378:metabolism; D010052:Ovariectomy; D010766:Phosphorylation / Q000187:drug effects; D010770:Phosphotransferases; D011374:Progesterone / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014443:Tyrosine; D014599:Uterus / Q000187:drug effects* / Q000378:metabolism
D014443:Tyrosine; D011374:Progesterone; D004958:Estradiol; D010770:Phosphotransferases; D017871:Calcium-Calmodulin-Dependent Protein Kinases