Age-related changes in mRNA, protein and catalytic activity of hepatic neutral cholesterol ester hydrolase in male rats: evidence for transcriptional regulation.
Messenger RNA, protein mass and catalytic activity of hepatic neutral cholesteryl ester hydrolase (CEH) were measured in male Sprague-Dawley rats, aged 6, 8, 9.5, 12 and 24 weeks (wks). CEH mRNA increased 101% from 6 to 9.5 wks, corresponding to onset of puberty, and declined by 52% from 12 to 24 wks. CEH mass was highly correlated with mRNA levels at all ages, increasing 170% from 6 to 9.5 wks and declining 61% from 12 to 24 wks. CEH activity was highly correlated with mass and mRNA from 8-24 wks, but was greater at 6 wks than the activity predicted by the measured mass. In all age groups, activity was consistently increased by activation of endogenous protein kinase A and consistently inhibited by alkaline phosphatase, suggesting that age-related differences in catalytic activity were not due to differences in the level of enzyme phosphorylation. These data suggest transcriptional regulation and indicate an important role for CEH in cholesterol homeostasis in the developing rat.
Natarajan
R
R
Department of Biochemistry and Molecular Biophysics, Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0614, USA.
Ghosh
S
S
Grogan
W M
WM
D000375:Aging; D000818:Animals; D015153:Blotting, Western; D002384:Catalysis; D000242:Cyclic AMP / Q000494:pharmacology; D005786:Gene Expression Regulation; D008099:Liver / Q000201:enzymology*; D008297:Male; D011494:Protein Kinases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D002787:Sterol Esterase / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
D011506:Proteins; D012333:RNA, Messenger; D000242:Cyclic AMP; D011494:Protein Kinases; D002787:Sterol Esterase