Tissue-specific protein kinase C isoform expression in rat uterine tissue.
OBJECTIVE
Activation of the phosphatidylinositol signaling pathway plays a key role during the generation of agonist-stimulated phasic myometrial contractions. Protein kinase C (PKC), a component of this signaling pathway, has been previously shown to produce feedback inhibition of agonist-stimulated myometrial contractions. The studies described in this report were performed to survey the tissue-specific expression of several PKC isoforms in the rat uterus.


METHODS
Uterine tissue was obtained from timed pregnant and normally cycling adult female Sprague-Dawley rats. Immunohistochemical studies were performed using the Vectastain ABC immunostaining technique and PKC isoform-specific polyclonal antibodies. Western blot studies were performed using myometrial tissue separated into cytosol and membrane fractions by differential centrifugation.


RESULTS
These studies confirmed significant expression of the PKC-alpha, -beta 2, -delta, -eta, and -zeta isoforms in myometrium from pregnant and estrus rats, whereas only trace or no expression of the PKC-beta 1, -gamma, -epsilon, and -theta isoforms was observed. Expression of the PKC-alpha, -beta 2, and -eta isoforms decreased modestly during the latter days of gestation; in contrast, PKC-delta and -zeta remained stable during this period. The immunohistochemical studies confirmed expression of the PKC-alpha, -beta 2, -delta, -eta, and -zeta isoforms in both circular and longitudinal smooth-muscle layers of the near-term pregnant rat uterus.


CONCLUSIONS
In summary, these studies have confirmed significant levels of expression of several isoforms of PKC in estrus and near-term pregnant rat uterine tissue, which was most prominent in the smooth-muscle cells of the myometrium.
Kim
T T
TT
Department of Obstetrics and Gynecology, University of Chicago, IL 60637, USA.
Saunders
T
T
Bieber
E
E
Phillippe
M
M
D000818:Animals; D015153:Blotting, Western; D002462:Cell Membrane / Q000201:enzymology; D003600:Cytosol / Q000201:enzymology; D005260:Female; D005865:Gestational Age; D007150:Immunohistochemistry; D007527:Isoenzymes / Q000032:analysis / Q000378:metabolism*; D009215:Myometrium / Q000201:enzymology; D011247:Pregnancy; D011493:Protein Kinase C / Q000032:analysis / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014599:Uterus / Q000201:enzymology*
D007527:Isoenzymes; D011493:Protein Kinase C