Diurnal variation and cholesterol regulation of hepatic HMG-CoA reductase activity

David J. Shapiro; Victor W. Rodwell

doi:10.1016/0006-291X(69)90972-3

Diurnal variation and cholesterol regulation of hepatic HMG-CoA reductase activity

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Abstract

HMG-CoA reductase exhibits a diurnal rhythm. Cycloheximide injection completely prevents both the observed 9.5 fold rise in activity and the loss of activity during daylight. This is compatible with the existence of a specific, labile,degradative or inactivating protein for HMG-CoA reductase. Effects of cholesterol on reductase activity were also studied. K_M and V_max for reductase from normal- and cholesterol-fed rats are 8.1×10^-5 M and 0.33 nmole/min/mg and 6.9x10^-5 M and 0.0404 nmole/min/mg respectively. Reductase from both sources is substrate-inhibited by HMG-CoA. Mixing experiments suggest that a soluble inhibitor of IM -CoA reductase does not cause the profound drop in activity observed in cholesterol-fed rats.

Original language	English (US)
Pages (from-to)	867-872
Number of pages	6
Journal	Biochemical and Biophysical Research Communications
Volume	37
Issue number	5
DOIs	https://doi.org/10.1016/0006-291X(69)90972-3
State	Published - Nov 20 1969
Externally published	Yes

ASJC Scopus subject areas

Biophysics
Biochemistry
Molecular Biology
Cell Biology

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10.1016/0006-291X(69)90972-3

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title = "Diurnal variation and cholesterol regulation of hepatic HMG-CoA reductase activity",

abstract = "HMG-CoA reductase exhibits a diurnal rhythm. Cycloheximide injection completely prevents both the observed 9.5 fold rise in activity and the loss of activity during daylight. This is compatible with the existence of a specific, labile,degradative or inactivating protein for HMG-CoA reductase. Effects of cholesterol on reductase activity were also studied. KM and Vmax for reductase from normal- and cholesterol-fed rats are 8.1×10-5 M and 0.33 nmole/min/mg and 6.9x10-5 M and 0.0404 nmole/min/mg respectively. Reductase from both sources is substrate-inhibited by HMG-CoA. Mixing experiments suggest that a soluble inhibitor of IM -CoA reductase does not cause the profound drop in activity observed in cholesterol-fed rats.",

author = "Shapiro, {David J.} and Rodwell, {Victor W.}",

note = "Funding Information: liver HMG-CoAr eductase activity and the effects of cholesterol on reductase lAbbreviations used: HI%, 3-hydroxy-3-methylglutaric acid; MVA, mevalonic acid. *Supported by grants from the National Science Foundation (GB 8321) and from the Indiana Heart Association. Journal paper #3843 of the Purdue University Agricultural Experiment Station. 3Predoctoral Fellow of the National Institutes",

year = "1969",

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doi = "10.1016/0006-291X(69)90972-3",

language = "English (US)",

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T1 - Diurnal variation and cholesterol regulation of hepatic HMG-CoA reductase activity

AU - Shapiro, David J.

AU - Rodwell, Victor W.

N1 - Funding Information: liver HMG-CoAr eductase activity and the effects of cholesterol on reductase lAbbreviations used: HI%, 3-hydroxy-3-methylglutaric acid; MVA, mevalonic acid. *Supported by grants from the National Science Foundation (GB 8321) and from the Indiana Heart Association. Journal paper #3843 of the Purdue University Agricultural Experiment Station. 3Predoctoral Fellow of the National Institutes

PY - 1969/11/20

Y1 - 1969/11/20

N2 - HMG-CoA reductase exhibits a diurnal rhythm. Cycloheximide injection completely prevents both the observed 9.5 fold rise in activity and the loss of activity during daylight. This is compatible with the existence of a specific, labile,degradative or inactivating protein for HMG-CoA reductase. Effects of cholesterol on reductase activity were also studied. KM and Vmax for reductase from normal- and cholesterol-fed rats are 8.1×10-5 M and 0.33 nmole/min/mg and 6.9x10-5 M and 0.0404 nmole/min/mg respectively. Reductase from both sources is substrate-inhibited by HMG-CoA. Mixing experiments suggest that a soluble inhibitor of IM -CoA reductase does not cause the profound drop in activity observed in cholesterol-fed rats.

AB - HMG-CoA reductase exhibits a diurnal rhythm. Cycloheximide injection completely prevents both the observed 9.5 fold rise in activity and the loss of activity during daylight. This is compatible with the existence of a specific, labile,degradative or inactivating protein for HMG-CoA reductase. Effects of cholesterol on reductase activity were also studied. KM and Vmax for reductase from normal- and cholesterol-fed rats are 8.1×10-5 M and 0.33 nmole/min/mg and 6.9x10-5 M and 0.0404 nmole/min/mg respectively. Reductase from both sources is substrate-inhibited by HMG-CoA. Mixing experiments suggest that a soluble inhibitor of IM -CoA reductase does not cause the profound drop in activity observed in cholesterol-fed rats.

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Diurnal variation and cholesterol regulation of hepatic HMG-CoA reductase activity

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