Measurement of hepatic sterol synthesis in the Mongolian gerbil in vivo using (/sup 3/H)water: diurnal variation and effect of type of dietary fat

Journal Article · Thu Jan 01 04:00:00 EST 1981 · J. Lipid Res.; (United States)

OSTI ID:5672941

Mercer, N J; Holub, B J

The hepatic synthesis of sterol was measured in the male Mongolian gerbil (Meriones unguiculatus) in vivo following the administration of (/sup 3/H)water by monitoring the incorporation of radioactivity into digitonin-precipitable sterol. A diurnal rhythm in cholesterol synthesis was exhibited under conditions of ad libitum feeding with alternating 12-hour periods of light (0200 to 1400 hr) and dark (1400 to 0200 hr). The zenith was reached between 1500 and 2100 hr and the nadir approximately 10-12 hours later between 0200 and 0400 hr, which provided a zenith/nadir ratio of 9.6 to 1.0. The in vivo rates of hepatic sterol synthesis and plasma cholesterol levels were measured in gerbils fed semi-purified diets containing either 19.5% beef tallow + 0.5% safflower, 20% lard, or 20% safflower oil and widely differing ratios of polyunsaturated: saturated fatty acids. All diets were equalized to contain 0.01% cholesterol and 0.05% plant sterol. After 3 days on the experimental diets, the mean rates of cholesterol synthesis (nmol/g liver per hr) were 41.5, 26.6, and 13.8 for animals fed the diets containing beef tallow, lard, and safflower oil, respectively. After 7 and 14 days, synthetic rates were lowest in the gerbils fed safflower oil as were also the plasma cholesterol levels. These results indicate that the type of dietary lipid can significantly influence the in vivo rate of sterol biosynthesis in gerbil liver. This response may contribute, at least in part, to the observed differences in plasma cholesterol levels.

• Research Organization: Department of Nutrition, University of Guelph, Ontario, Canada
• OSTI ID: 5672941
• Journal Information: J. Lipid Res.; (United States), Journal Name: J. Lipid Res.; (United States) Vol. 22:5; ISSN JLPRA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
BIOLOGICAL EFFECTS
BIOSYNTHESIS
BODY
CHOLESTEROL
DAILY VARIATIONS
DIET
DIGESTIVE SYSTEM
DRINKING WATER
FATS
GERBILS
GLANDS
HYDROGEN COMPOUNDS
HYDROXY COMPOUNDS
IN VIVO
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LIVER
MAMMALS
ORGANIC COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
RODENTS
STEROIDS
STEROLS
SYNTHESIS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VARIATIONS
VERTEBRATES
WATER