Liver lipids of rats administered excessive amounts of retinol

Abstract

Effect of intramuscular administration of 100 000 I.U. of retinol daily for 13 days on the liver lipid metabolism of young rats was studied. Intramuscular administration of excessive amounts of retinol did not affect the body weights or the daily food consumption. Retinol-treated rats showed a significant enlargement of the liver compared with controls. The values for liver total lipids, total cholesterol, total glycerides, total fatty acids, and retinol were 59.9 ± 0.9, 2.5 ± 0.1, 24.2 ± 1.3, 27.9 ± 1.8, and 1.35 ± 0.14 mg/g wet tissue, respectively, in retinol-treated compared with control values of 37.0 ± 0.9, 1.8 ± 0.06,9.5 ± 0.46, 17.6 ± 1.5, and 0.024 ± 0.008. The effect of excess retinol administration on liver neutral lipids and phospholipids was studied by thin-layer chromatography. Retinol administration caused significant increases in the concentrations of free cholesterol, esterifled cholesterol, monoglycerides, triglycerides, lysophosphatidylcholine, phosphatidylcholine, and phosphatidylethanolamine, and significant decreases in the concentration of phosphatidylinositol.

Retinol and Adrenal Lipids of Rats

“…Whether this is a direct or indirect effect of vitamin A is not certain at this stage, but similar results have been reported by Rao and Olson (3) and Misra (13) in liver of hypervitaminotic A rats. The increase observed in adrenal glycerides was accompanied by a simultaneous decrease in both monoglycerides and diglycerides (Table 2).…”

“…The decrease noted in mono and diglycerides (Table 2), point out towards an enhanced synthesis and accumulation of triglycerides in adrenals of rats fed retinol as compared to the control rats. An increase in total hepatic lipids, glycerides and fatty acids in livers of hypervitaminotic A rats have similarly been observed (13,14). In view of Gillman and Gilbert (16,17) suggestion on the role of endocrine gland metabolism in the production of nutritional fatty liver and deposition of glycogen in liver, it can be conceived that the stimulated metabolism of adrenals in excess retinol fed rats may have some role in fatty liver production and increased amounts of liver glycogen, observed in hypervitaminotic A rats (18).…”

Detection of Retinyl Palmitate and Retinol in the Liver of Mice Injected with Excessive Amounts of Retinyl Acetate.

“…Pharmacological doses of synthetic VA (isotretinoin, acitretin) have been shown to have a beneficial effect in the treatment of a variety of skin conditions such as acne and psoriasis, as well as some neoplasms of epithelial origin [4]. However, excessive retinoic acid, retinol or retinyl acetate ingestion or injection has been linked to teratogenesis and to alterations in lipid metabolism in humans and animals [1,7,8,18].…”

“…The transport of subcutaneously injected retinyl acetate (RA, 100,000 IU/mouse, 105,470 nM) was investigated in male ICR mice (10-week-old) at 0, 3,6,12,18,24 and 72 hr after a single injection. The retinol and retinyl palmitate levels of liver homogenates, bile in the gallbladder and serum from peripheral blood were measured by high performance liquid chromatography (HPLC) method.…”

“…The effects of hypervitaminosis A on liver metabolism have been extensively investigated by feeding or injecting multiple doses of synthetic derivatives of retinol or natural forms of VA over many days [5,7,18,24]. The effect of subcutaneous injection of esterified forms of VA (retinyl acetate or palmitate) has been mainly reported with increase of VA lipid droplets in Ito cells after few days [29,30].…”