Time Course of Changes in Rat Serum Apolipoproteins during the Consumption of Different Low Protein Diets Followed by a Balanced Diet

Abstract

The effects of protein malnutrition (PM) followed by refeeding a balanced diet on apolipoprotein and lipid contents of the serum lipoproteins were studied in young Wistar male rats. The changes of serum apolipoproteins were compared with the appearance of fatty liver during PM and its disappearance during refeeding. The control group (T) was fed a balanced diet containing 15% casein for 42 d. Two depleted groups (C) and (G1) were fed for 28 d low protein diets containing 2% casein and 5% gluten, respectively, and then were fed the balanced diet for 14 d. During PM a concentration of triacylglycerols (TGs) in liver in the two depleted groups increased; the level in rats fed 2% casein was twice that in rats fed 5% gluten. There was a significant negative correlation between serum TGs and liver TGs. The serum apolipoproteins (apo) did not respond consistently. The high-density lipoproteins apo A-I, A-II and A-IV, which are more than 50% synthetized in the intestine, remained essentially unchanged, thus showing resistance to protein malnutrition. The very low density lipoproteins apo B and total apo C, which mainly originate from liver, were significantly lower in malnourished groups than in controls, while the liver TGs accumulated in malnourished groups. Only the levels of total apo C and apo B48 were correlated with hepatic TG steatosis during malnutrition and refeeding.

Impaired lipoprotein metabolism in obese offspring of streptozotocin‐induced diabetic rats

“…Twelve pregnant dams were injected with citrate buffer alone as a control group. On days 13,16,18, and 20 of gestation, maternal blood was collected for plasma glucose concentrations by cutting off the tip of tail and squeezing it gently. Pregnant rats with plasma glucose levels between 5.55 and 16.65 mmol/L (compared with 5 mmol/L in controls) were designated as mildly hyperglycemic (13) and were included in the study.…”

“…Serum lipoproteins of density <1.21 kg/L were isolated by single ultracentrifugation flotation (Model L8-55 ultracentrifuge, 50 Ti rotor; Beckman Instruments, Palo Alto, CA), according to Havel et al (16). The three fractions (VLDL, LDL-HDL 1 , HDL 2-3 ) were isolated from total lipoproteins by a single-spin discontinuous gradient according to the method of Redgrave et al (17) as modified by Meghelli-Bouchenak et al (18). Purified fractions of VLDL (d < 1.006), LDL-HDL 1 (1.006 < d < 1.06), and HDL 2-3 (1.06 < d < 1.21) were dialyzed against 0.15 mol/L NaCl and 1 mmol/L disodium EDTA, pH 7.4, at 4°C in spectra/por 2 dialysis tubing (Spectrum Laboratories, Rancho Dominguez, CA).…”

Lecithin-cholesterol acyltransferase activity during two types of protein malnutrition followed by balanced refeeding in the growing rat

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Our earlier studies (Meghelli-Bouchenak et al, 1987, 1989a Knipping (1986).In the T group (15% casein), a reduction in LACT activity with age was noted. The onset of both types of PM promoted the same significant decrease in LCAT activity (P < 0.05).

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“…Our earlier studies (Meghelli-Bouchenak et al, 1987, 1989a Glomset et al (1964) modified by Knipping (1986).…”

Metabolism of triglyceride-rich emulsions in rats with protein malnutrition.

“…Those findings were also reported in children with kwashiorkor. Rats under pro longed protein depletion have been reported to display either normal or decreased plasma levels of TG and cho lesterol [17][18][19].…”