Hepatic apolipoprotein B synthesis in copper‐deficient rats

Abstract

The present study was designed to examine if induction of apolipoprotein B synthesis is associated with hypercholesterolemia in copper-deficient rats. This hypercholesterolemia mainly resides in an increase in the HDL-1 and LDL and is associated with a significant increase in plasma apoB concentration. Liver apoB mRNA levels were not significantly modified in deficient animals as compared to control rats. Studies on liver apolipoprotein synthesis indicated that apoBlO0 synthesis was increased in deficient animals whereas apoB48 synthesis was unchanged. Thus, it appears that the increase in apoB synthesis in the liver of copper-deficient rats occurs at the posttranscriptional level. The selective increase in apoBlO0 synthesis indicates the possible impact of this deficiency on the editing of apoB. An increase in apoBlO0 synthesis by the liver in copper-deficient rats may significantly contribute to the increase in plasma concentration of LDL.

The Role of Copper as a Modifier of Lipid Metabolism

“…The plasma levels of apolipoproteins A, B, and E increase in rats fed a copper deficient diet, consistent with the increased particle numbers and sizes (35)(36)(37)(38)(39). Remarkably, hepatic apoA1, ApoE and ApoB mRNA levels remain unchanged, suggesting that the alteration of the apolipoprotein levels is not due to an increase in transcription.…”

“…Remarkably, hepatic apoA1, ApoE and ApoB mRNA levels remain unchanged, suggesting that the alteration of the apolipoprotein levels is not due to an increase in transcription. Indeed, it was found that hepatic synthesis and secretion rates of apoA1 are upregulated (35), whereas the rates of synthesis of ApoB-48 and ApoB-100 are unchanged, despite an increase in secretion (37). Intestinal secretion of apoA-1 was also observed, providing yet another source for increased circulating apolipoproteins and cholesterol (40).…”

Dietary Mineral Sources Altered Lipid and Antioxidant Profiles in Broiler Breeders and Posthatch Growth of Their Offsprings

“…Zn might affect lipid metabolism by alteration of apolipoprotein expression. Moreover, Cu, Mn, and Se were also reported to be associated with apo B [10], apo E [9], and apo A [7] synthesis, which playing critical roles in lipoprotein metabolism. Different sources of minerals might change lipid metabolism by regulating apolipoprotein synthesis.…”

“…Cu, Zn, Mn, and Se were found to be important for apolipoprotein (apo), the major structural protein of lipoprotein, so as to participate in lipid metabolism [7][8][9][10][11]. Cu, Zn, Mn, and Se are also essential for catalytic activity and proper spatial conformation of antioxidant enzymes such as superoxide dismutase (SOD), catalase, and glutathione peroxidase (GSH-Px) and thereby play important roles in the antioxidant defense and lipid peroxidation [12].…”

Cardiovascular effects of dietary copper deficiency

“…The occurrence and metabolic development of hypercholesterolemia in copper deficiency have been reviewed [108] and updated by further recent study (e.g., [109][110][111][112].…”