Vitamin A transport in plasma of diabetic patients.

Abstract

The effects of diabetes on the vitamin A metabolism were studied. The concentrations of plasma retinol and retinyl ester were measured in diabetic patients using high-performance liquid chromatography (HPLC). In diabetic patients, the mean level of retinyl ester was significantly elevated compared to that of normal subjects (diabetes, 68.3+42.5 IU/100 ml of plasma ; study I, 87.6+64.3 IU/100 ml of plasma ; study II vs. normal, 29.8+ 10.3 IU/100 ml of plasma). The ultracentrifugal and column chromatographic studies were carried out to examine the distribution of retinyl ester in patient's plasma. Ultracentrifugation study showed that the mean of 72.6° of retinyl ester was recovered in the lipoproteins of density higher than 1.006 and the remainder was recovered in the chylomicron (d < 1.006). Gel filtration profiles for the separation of plasma vitamin A demonstrated that retinyl ester presented in the HDL, LDL and larger molecular size lipoprotein (suspected to be VLDL) as well as in the chylomicron. vitamin A ; diabetes ; plasma lipoprotein

Effect of Insulin Treatment or Zinc Supplementation on Vitamin A Status in Streptozotocin-Induced Diabetic Rats.

“…These results are in agreement with earlier studies on humans or rats [1][2][3][4][5][6][7]. The increased liver concentrations of vitamin A may be explained in part by the increased food intake by the diabetic animals (>50%), since it has been shown that the hepatic storage of vitamin A is proportional to its intake [25].…”

“…It has further been shown that diabetic patients not only have reduced plasma retinol but also elevated levels of retinyl esters [4], reflecting an increased hepatic storage [5]. Streptozotocin (STZ)-induced diabetic rats have decreased plasma retinol levels that are accompanied by an elevated hepatic concentration of vitamin A [6].…”

Retinol, α-tocopherol and carotenoids in diabetes

“…Several studies have reported that serum levels of both carotene and vitamin A are within normal range in diabetes mellitus (Murrill et al, 1941;Kimble et al, 1946;Ramachandran, 1973). Recently, an increase in plasma retinyl esters has been reported in Type 2 diabetes (Wako et al, 1986) and a decrease in serum concentration of vitamin A and RBP in Type 1 diabetes (Basu et al, 1989). Other investigators found that retinol concentrations were signi®cantly decreased in Type 1 (Krempf et al, 1991) and increased in Type 2 diabetes mellitus as compared to control subjects (Krempf et al, 1991;Havivi et al, 1991;Sasaki et al, 1995).…”

Determination of Endogenous Levels of Retinoic Acid Isomers in Type II Diabetes Mellitus Patients. Possible Correlation with HbA1c Values.

“…Lower serum concentrations of retinol in patients with insulin-dependent diabetes (IDDM) and in streptozotocin-induced diabetic rats, in which the transport mechanism of retinol from liver to the target site is considered to be impaired, were reported. [1][2][3][4][5] In contrast, patients with non insulin-dependent diabetes (NIDDM) have greater serum retinol concentrations than normal subjects. [6][7][8] Recently, PPARg, a ligand-activated transcription factor and a member of the nuclear hormone receptor superfamily, was found to play a pivotal role in the expression of genes associated with metabolism and transport of glucose and lipids.…”