Prolactin-provoked alterations of cytosolic, membrane, and nuclear protein kinase C following partial hepatectomy.
The adenohypophyseal polypeptide hormone prolactin is a potent liver mitogen, stimulating cell cycle progression, an effect that appears coupled to increasing protein kinase C activity in membrane and nuclear fractions. Here, we examine whether hepatocyte proliferation, stimulated by partial hepatectomy, is associated with altered serum prolactin or protein kinase C activation. Within 5-15 min of liver resection, serum prolactin concentrations elevate significantly. Protein kinase C activity in hepatic cytosol decreases significantly, and membrane and nuclear PKC activity increase by 30 min. Hypophysectomy prior to partial hepatectomy abrogates any effect of liver resection on protein kinase C activation in the hepatic remnant. Based upon these data, it is suggested that the rapid increase in serum prolactin seen after partial hepatectomy may be linked to protein kinase C activation, which in turn stimulates the hepatic proliferative response that is essential for hepatic regeneration.
Buckley
A R
AR
Department of Pharmacology, Kirksville College of Osteopathic Medicine, Missouri 63501.
Crowe
P D
PD
Bauman
P A
PA
Neumayer
L A
LA
Laird
H E
HE
Russell
D H
DH
Putnam
C W
CW
D000818:Animals; D002455:Cell Division / Q000502:physiology; D006498:Hepatectomy; D007016:Hypophysectomy; D008099:Liver / Q000166:cytology / Q000201:enzymology*; D008115:Liver Regeneration / Q000502:physiology*; D008297:Male; D010903:Pituitary Gland, Anterior / Q000502:physiology; D011388:Prolactin / Q000097:blood / Q000502:physiology*; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D011388:Prolactin; D011493:Protein Kinase C