The effect of feeding and fasting on the activity of acyl-CoA: cholesterol acyltransferase in rat small intestine.
The purpose of the present study was to test if the microsomal acyl-CoA:cholesterol acyltransferase (ACAT) in rat small intestine is regulated under physiological conditions. Two previously described in vitro assays were used, both based on the esterification of endogenous cholesterol with exogenous acyl-CoA, performed or generated during the incubation. The important and consistent finding with rats on normal diet was an increase in ACAT activity with fasting and a decrease with feeding. Independent of the assay used, the ratio between ACAT activity in night-fasted and night-fed animals was about 2 (P less than 0.005). When the fasting period was extended to 36 h a corresponding difference was found whether the ACAT assay was based on preformed [1-14C]oleoyl- or [1-14C]palmitoyl-CoA as acyl-donor (P less than 0.05). The microsomal content of unesterified cholesterol was higher in fasted than fed animals, suggesting that availability of this substrate might be a factor in the regulation of rat intestinal ACAT activity.
D000214:Acyl Coenzyme A / Q000378:metabolism*; D000217:Acyltransferases / Q000378:metabolism*; D000818:Animals; D002940:Circadian Rhythm; D005247:Feeding Behavior / Q000502:physiology*; D005508:Food Deprivation / Q000502:physiology*; D007583:Jejunum / Q000201:enzymology*; D008029:Lighting; D008055:Lipids / Q000032:analysis; D008297:Male; D008861:Microsomes / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains; D002785:Sterol O-Acyltransferase / Q000378:metabolism*
D000214:Acyl Coenzyme A; D008055:Lipids; D000217:Acyltransferases; D002785:Sterol O-Acyltransferase