[Effects of vitamin A (retinol), Tioadenolo and a standard diet on the plasma lipid pattern in the rat on an atherogenic diet]. / Effetti della vitamina A (retinolo), del Tioadenolo e di una dieta standard sul quadro lipemico del ratto a dieta aterogena.

The Authors have examined the action of large doses of vitamin A (2000 U.I./Kg diet) compared with that obtained by administration of a lipid lowering drug (Tioadenolo) and a standard diet in albino rats feed at first an atherogenic diet for 15 days. The "recovering" diets were adminisetred for 15 and 30 days. Serum components were obtained with routine chemical-clinical assay, membrane lipids and related fatty acids by the method of Folch in erythrocytes isolated by the method of Wipple. Both retinol and Tioadenolo lower blood plasma and cell membrane lipids more than a standard diet.

[Uptake of retinol-C14 into different tissues of vitamin A deficient albino rats]. / Incorporazione di retinolo-C14 in differenti tessuti di ratti albini a dieta priva di vitamina A.

Groups of rats were fed a vitamin A free diet for 30, 60 and 90 days. They were then administered orally a single dose of 1,25 microC of retinol-C14. After 3 h, 3, 6 and 12 days from the administration, the incorporation into the different tissues was determined. The results show that the incorporation decreases, on the average, as the experimental period and the intervals after the administration of retinol-C14 grow longer.

[Uptake of retinol-C14 into liver mitochondrial membranes and erythrocyte stroma of albino rats on a vitamin A-free diet]. / Incorporazione di retinolo-C14 nelle membrane dei mitocondri epatici e nello stroma dei globuli rossi di ratti albini a dieta priva di vitamina A.

We have determined the incorporation of retinol-C14 into liver mitochondrial membranes and blood cell stroma in albino male Wistar strain rats, fed with a vitamin A deficient diet for 30, 60 and 90 days. At the end of the vitamin A deficient period, rats were kept fasting for 24 hours and then administered orally retinol-C14 (1,25 microC). They were divided into groups and killed after 3 hours, 3, 6, 12 days from the administration of retinol-C14. The incorporation is very high in one-month deficient rats, it decreases as the experimental period and the intervals after the administration of retinol-C14 grow longer.

[Distribution and depletion with time of retinol-C14 in different tissues and organs of albino rats]. / Distribuzione e deplezione nel tempo di retinolol-C14 in differenti tessuti ed organi di ratti albini.

Albino male rats of Wistar strain, weighing about 350 g., were administered orally a single dose of 2,50 mu C of retinol-C14 after a fast of 24 h. At intervals of 3 h and of 3, 6, 12, 18 and 24 days rats were killed; livers, kidneys, blood, white fat tissue and brown fat tissue were removed. Samples were dried and radioactivity was measured. From the results, expressed in mu C/g of dry tissue, it is clear that vitamin A is taken up by all tissues. After 3 days it decreases in all tissues, between the 3rd and 18th day, its rate is constant and the depletion is complete within 24 days.

[Variations of retinol-C14 incorporation in rats of different ages fed a vitamin A-free diet]. / Variazioni dell'incorporazione del retinolo-C14 in ratti di differente età alimentati con una dieta priva di vitamina A.

Two groups of Wistar strain male albino rats of different age were treated with a large dose (300 I.U.) of vitamin A-acetate, after 24 h fasting. Each rat was then administered orally a single dose of 1,25mu C retinol-C14 to determine the rate of incorporation into different tissues. At intervals of 3 h and of 3, 6, 12 days the rats were killed; liver, kidney, blood, white fat tissue, brown fat tissue were taken and dried. Radioactivity was measured. The results show that in all tissue the mean percentage of incorporation, expressed in muC/g dry tissue, is generally higher in young than in adult rats.

[Vitamin "A" and biological membranes. Nota VI-Fatty acid composition of liver mitochondrial membranes in vitamin A-deficient rats (author's transl)]. / Vitamina "A" e membrane biologiche. Nota VI-Composizione in acidi grassi delle membrane dei mitocondri epatici di ratti albini in avitaminosi A

The results we obtained in studying the fatty acid composition of erythrocyte stroma on vitamin A-deficient rats, led us to repeat the experiment on liver mitochondrial membranes. Two groups of albino male rats, of the Wistar strain, were fed for 90 days with a balanced and a vitamin A-free diet respectively. The animals were killed, total lipid from the membranes of liver mitochondria were extracted and fatty acids separated by gas-chromatography. It was noticed an increase in the percentage of saturated fatty acids; at the same time, mono and polyunsaturated fatty acids decreased. The results agree with those obtained in rats fed for 30 and 60 days with vitamin A-free diet. This seems to support the interpretation that vitamin A modifies, to some extent, the metabolism of polyunsaturated fatty acids.

[Vitamin "A" and biological membranes. Nota V - Fatty acid composition of erythrocyte stroma in vitamin A deficient rats (author's transl)]. / Vitamina "A"' e membrane biologiche. Nota V - Composizione in acidi grassi degli stromi degli eritrociti di ratti albini in avitaminosi A

Two groups of albino male rats, were fed for 90 days with a balanced and vitamin A-free diet rispectively, to observed changes, if any, in the fatty acid composition of erythrocyte membranes. The blood was separated with heparin, total lipids from erythocyte stroma were extracted and fatty acids analyzed by gaschromatography. It was noticed an increase in saturated fatty acids; at the same time mono- and, above all, polyunsaturated fatty acids decreased; the results agree with those obtained in rats fed for 30 and 60 days with Vitamin A-free diet as similar changes were observed in liver mitochondrial membranes of the rats, under study, we presume vitamin A modifies, to some extent, the biosyntesis of unsaturated fatty acids.