The effect of dietary lipid on the lipoprotein status of the mongolian gerbil

Abstract

The Mongolian gerbil, Meriones unguiculatus, may be a suitable animal model for the investigation of dietary lipid effects on cholesterol metabolism. The effects of dietary cholesterol, and its possible interaction with the type of dietary fat, on the lipoprotein status of this animal have not been examined previously. In the present research, the effects of adding 0.5% cholesterol to diets high in saturated (19.5% beef tallow: 0.5% safflower oil) or polyunsaturated (20% safflower oil) fats on the lipoprotein status of the gerbil were determined after 11 and 22 days of feeding. Lipoproteins (VLDL, LDL and HDL) were separated by sequential ultracentrifugation. Their cholesterol, phospholipid and protein concentrations were determined colorimetrically. In the absence of 0.5% cholesterol, safflower oil lowered the concentration (mg/100 ml) of cholesterol in each of the VLDL, LDL and HDL relative to beef tallow (BT) without greatly influencing the cholesterol distribution amongst them. The HDL carried the majority of the serum cholesterol and the VLDL transported the smallest amount. However, inclusion of 0.5% dietary cholesterol resulted in a redistribution of cholesterol amongst the lipoproteins so that the VLDL and LDL became the major and the HDL the minor carriers. Dietary cholesterol also brought about a rise in the VLDL and LDL concentrations (mg/100 ml) of cholesterol, phospholipid and protein and altered the VLDL and LDL compositions. No such changes were observed in the HDL, indicating that the HDL are relatively resistant to any of the possible effects of cholesterol feeding measured in this experiment. The specific mechanisms responsible for the changes observed in the lipoprotein status of the gerbil remain to be elucidated.

Long-Term and Short-Term Effects of Dietary Cholesterol and Fats in the Mongolian Gerbil

“…Identical results in gerbils have been found by other investigators [11]: after a 22-day diet the serum cholesterol in gerbils on SSO and 0.5% of cholesterol was signifi cantly higher than in gerbils on beef tallow and 0.5% cholesterol. This hypocholesterolemic effect of saturated fats, in our case PO, illustrates that under pathological conditions paradoxical results can be obtained.…”

“…Although highly resistant to ath erosclerosis [3,8] the gerbil has been advo cated as a suitable animal model to evalu ate the influence of dietary cholesterol and fats on lipoprotein metabolism [1,16,17], The influence of various dietary fats on se rum cholesterol in the gerbil resembles to some extent that in man [16], although there are some differences in the response of lipoprotein-cholesterol [11]. In some of these studies mentioned above an excessive storage of cholesterol ester in the liver has been reported [1,2,7,8,16,19], Besides this cholesterol ester storage in the liver, the gerbils stayed in good health.…”

Biology and Diseases of Other Rodents

“…However, because of the fat metabolism of gerbils, they develop high blood cholesterol concentrations on diets containing more than LABORATORY ANIMAL MEDICINE 4% fat (Leach and Holub, 1984;Nicolosi et al, 1981;Temmerman et al, 1988). Zeman (1967) described a semi-purified diet for gerbils, and in the laboratory, gerbils thrive on commercially available pelleted rodent diets.…”

Hydroxylation of fatty acids and alcohols by hepatic microsomal cytochrome P‐450 system from the Mongolian gerbil

“…Although mammals such as rat, mouse, guinea pig or rabbit are generally used in both basic and clinical research, some mammals other than these have been successfully developed as novel experimental animals (1 4) and used for a variety of specific research (5)(6)(7). In a previous paper (8), we described the substrate specificity and other properties of a fatty acid hydroxylase system in the liver microsomes of the house musk shrew (Suncus murinus), which has received attention as a possible laboratory animal because of such desirable traits as small size, rapid breeding and environmental flexibility.…”

“…Abbreviations: PCMB, p-chloromercuribenzoate; SDS, sodium dodecylsulfate. years (7,(9)(10)(11)(12). However, no information is available concerning the fatty acid hydroxylating system in the gerbil liver.…”