Cholesteryl Ester Depletion Research Articles

Circulating lipids and lipoproteins in glycogen storage disease type I with nocturnal intragastric feeding.

With the advent of nocturnal intragastric feeding which protects against acute metabolic complications and promotes growth, patients with glycogen storage disease type I are attracting less attention. However, several biochemical alterations persist and suggest that the long-term risk of atherosclerotic heart disease remains high. Persisting hypertriglyceridemia and hypercholesterolemia were found in seven glycogen storage disease type I subjects, six of them following 5-6 yr of nocturnal intragastric feeding. When compared to ten age-matched controls, the patients showed significantly (P less than 0.001) higher low density lipoprotein cholesterol (LDL-C) (247.7 +/- 46.8 vs. 115.3 +/- 5.0 mg/dl) and lower high density lipoprotein cholesterol (HDL-C) (26.4 +/- 3.4 vs. 55.8 +/- 2.9 mg/dl). Triglyceride (TG) enrichment with cholesteryl ester depletion characterized the lipoprotein classes. The diameters of very low density lipoproteins (VLDL) and LDL were larger, while that of HDL was smaller and consistent with the predominance of the HDL3 subclass and a lower apoA-I/apoA-II ratio. The raised levels of TG appeared attributable not only to the well-described lipogenesis, but also to impaired catabolism of fat, as evidenced by the significantly (P less than 0.001) decreased activity of both peripheral lipoprotein lipase (3.17 +/- 0.43 vs. 14.15 +/- 0.50 mumol FFA.ml-1.hr-1) and hepatic lipase (1.88 +/- 0.30 vs. 4.83 +/- 0.90). This may well explain the high concentration of intermediate density lipoprotein (IDL) and the impaired conversion of HDL3 to HDL2. Low apoC-II/apoC-III1 could be related to defective lipoprotein lipase activity. These data suggest that glycogen storage disease type I patients on nocturnal intragastric feeding remain at risk for atherosclerosis and its complications.

Cholesteryl ester depletion from the ovaries of superovulated female rats fed a normal or essential fatty acid deficient diet.

The cholesteryl ester content of the ovaries was determined in rats diets containing corn oil or hydrogenated coconut oil (essential fatty acid (EFA) deficient) and subjected to superovulation by injection of luteinizing hormone and follicle-stimulating hormone. Superovulation increased ovarian weight; the effect was greater in animals fed corn oil. Superovulation significantly decreased total ovarian cholesteryl ester concentration in animals fed corn oil, with disproportionately large decreases occurring in the esters of 20:1, 20:2, 22:5w6, and 22:6w3. Significant decreases were observed in these esters when the data were expressed on a unit mass of tissue basis or in relation to total ovarian mass. In superovulated, EFA-deficient rats, esters of 18:1, 20:1, 22:5w6, and 22:6w3 were significantly lower per unit mass of tissue but this was due, in all cases except that of 22:6w3, to the increased mass of ovarian tissue; there was no decrease in total esters per ovary weight during superovulation of deficient rats. The pattern and degree of selective changes in ovarian cholesteryl esters during superovulation were different from those previously reported for adrenal esters of stressed rats.

Effect of 4-Aminopyrazolopyrimidine and Aminoglutethimide on Cholesteryl Metabolism and Steroidogenesis in the Rat Adrenal*

The interrelationship between adrenal cholesteryl ester metabolism and steroidogenesis was examined by using 4-aminopyrazolopyrimidine (4-APP) and aminoglutethimide under in vivo and in vitro conditions. In vivo administration of 4-APP resulted in a reduction of plasma corticosterone and a diminished steroidogenic response to injected ACTH. After a 4-day recovery from 4-APP treatment, basal corticosterone levels remained low, but responsiveness to ACTH administration was observed. These steroidogenic effects were correlated with changes in plasma and adrenal cholesterol concentrations. Administration of aminoglutethimide prevented depletion of adrenal cholesteryl esters which occurred in response to 4-APP treatment alone, and also prevented the stress-induced cholesteryl ester depletion in response to unilateral adrenalectomy. Adrenal cell suspensions were used to study further the effect of aminoglutethimide and 4-APP on adrenal cholesterol metabolism. Suspensions prepared from 4-APP-treated animals were...

Effect of the stress of unilateral adrenalectomy on the depletion of individual cholesteryl esters in the rat adrenal

Normal rats were subjected to unilateral adrenalectomy and were killed 3 hr later. The concentration and composition of the cholesteryl esters in adrenals removed at operation and after death were compared. The esterified cholesterol concentration was lower in the adrenals obtained 3 hr after surgery. Cholesteryl arachidonate decreased in concentration significantly more than any other ester, followed in order of magnitude by linoleate and oleate. The cholesteryl ester concentration of adrenals removed from sham-operated rats 3 hr after surgery was also greatly reduced. On the basis of comparison with other work on the hydrolysis of cholesteryl esters by adrenal homogenates, it is concluded that the apparent selectivity in depletion of cholesteryl esters is due to differences in their rates of hydrolysis.