PHOSPHOLIPID METABOLISM IN RAT LIVER SLICES: EFFECT OF HYPOPHYSECTOMY AND ADRENALECTOMY ON THE LABELLING OF PHOSPHOLIPIDS WITH ACETATE-1-C14

1957 ◽  
Vol 35 (2) ◽  
pp. 143-150 ◽  
Author(s):  
Dorothy Kline ◽  
R. J. Rossiter
Keyword(s):  
Fatty Acids ◽  
Nutritional Status ◽  
Rat Liver ◽  
Adrenal Glands ◽  
Soluble Fraction ◽  
Phospholipid Metabolism ◽  
Acetone Insoluble ◽  
Liver Slices ◽  
Ad Libitum

In rats fed ad libitum the labelling of the acetone-insoluble lipids (phospholipids) of liver slices respiring in the presence of acetate-1-C14 was decreased 2 days after the removal of either the pituitary or the adrenal glands. The effect was not observed 4 days after hypophysectomy. Moreover, the effect was not observed with liver slices from hypophysectomized or adrenalectomized animals that were either deprived of food for the 12 hours immediately prior to killing, or force-fed with glucose 4 hours before killing. Hypophysectomy caused a decrease in the labelling of the fatty acids in the acetone-soluble fraction remaining in solution after precipitation of the phospholipids. This decrease was observed both in liver slices from animals fed ad libitum and in those from fasted (12 hours) animals. In rats fed ad libitum the labelling of the non-esterified cholesterol of the liver slices was decreased by hypophysectomy, but not by adrenalectomy. It is concluded that the decrease in the labelling of the acetone-insoluble lipids in liver slices from operated rats was primarily the result of a change in the nutritional status of the operated animals. The data are insufficient to permit any conclusions concerning the cause of the decrease in labelling of either the fatty acids of the acetone-soluble lipids, or the non-esterified cholesterol.

PHOSPHOLIPID METABOLISM IN RAT LIVER SLICES: EFFECT OF HYPOPHYSECTOMY AND ADRENALECTOMY ON THE LABELLING OF PHOSPHOLIPIDS WITH ACETATE-1-C14

1957 ◽  
Vol 35 (1) ◽  
pp. 143-150 ◽  
Author(s):  
Dorothy Kline ◽  
R. J. Rossiter
Keyword(s):  
Fatty Acids ◽  
Nutritional Status ◽  
Rat Liver ◽  
Adrenal Glands ◽  
Soluble Fraction ◽  
Phospholipid Metabolism ◽  
Acetone Insoluble ◽  
Liver Slices ◽  
Ad Libitum

In rats fed ad libitum the labelling of the acetone-insoluble lipids (phospholipids) of liver slices respiring in the presence of acetate-1-C14 was decreased 2 days after the removal of either the pituitary or the adrenal glands. The effect was not observed 4 days after hypophysectomy. Moreover, the effect was not observed with liver slices from hypophysectomized or adrenalectomized animals that were either deprived of food for the 12 hours immediately prior to killing, or force-fed with glucose 4 hours before killing. Hypophysectomy caused a decrease in the labelling of the fatty acids in the acetone-soluble fraction remaining in solution after precipitation of the phospholipids. This decrease was observed both in liver slices from animals fed ad libitum and in those from fasted (12 hours) animals. In rats fed ad libitum the labelling of the non-esterified cholesterol of the liver slices was decreased by hypophysectomy, but not by adrenalectomy. It is concluded that the decrease in the labelling of the acetone-insoluble lipids in liver slices from operated rats was primarily the result of a change in the nutritional status of the operated animals. The data are insufficient to permit any conclusions concerning the cause of the decrease in labelling of either the fatty acids of the acetone-soluble lipids, or the non-esterified cholesterol.

Effect of saturated fat diets on rat liver NADP-linked enzymes

1965 ◽  
Vol 209 (4) ◽  
pp. 773-780 ◽  
Author(s):  
Helen M. Tepperman ◽  
Jay Tepperman
Keyword(s):  
Fatty Acids ◽  
Enzyme Activity ◽  
Rat Liver ◽  
Corn Oil ◽  
Saturated Fat ◽  
Coconut Oil ◽  
Liver Slices ◽  
Fat Diets ◽  
Effect Of Feeding

The aggregate hexosemonophosphate dehydrogenase (HMPD) activity was found to be higher in livers of rats fed a diet containing saturated fat (hydrogenated coconut oil = H) for 7 days and fasted for 48 hr than it was in similarly prepared animals fed a corn oil (CO) diet. Later, a liver HMPD-increasing effect of feeding H was found in nonfasted animals. Lipogenesis (i.e., the incorporation of acetate-1-C14 into fatty acids by liver slices) was shown to be as low or lower in the H group as in the CO. Liver slices prepared from H and CO diet adapted rats were incubated with either acetate-1-C14 or palmitate-1-C14 and the extent of incorporation of C14 into individual fatty acids was measured. With both substrates more radioactivity was found in 16:1, 18:0, and 18:1 in the case of H-fed animals. It is proposed that a component of the signal for eliciting increased NADP-linked enzyme activity in the H rats was an increased rate of oxidation of NADPH attendant on monoene formation and chain lengthening.

EFFECTS OF HYPOGLYCIN A ON THE METABOLISM OF AMINO ACIDS BY LIVER SLICES

1964 ◽  
Vol 42 (1) ◽  
pp. 139-142 ◽  
Author(s):  
S. J. Patrick ◽  
L. C. Stewart
Keyword(s):  
Amino Acids ◽  
Fatty Acids ◽  
Fatty Acid ◽  
Glutamic Acid ◽  
Rat Liver ◽  
Inhibitory Effects ◽  
Liver Slices

The effects of hypoglycin A on the metabolism of L-leucine-C14, L-alanine-C14, and L-glutamic-acid-C14 by rat liver slices have been investigated. Hypoglycin exerted markedly inhibitory effects on the conversion of leucine-C14 to fatty acid, cholesterol, and CO2. Conversion of alanine-C14 and glutamic acid-C14 to fatty acids was also inhibited by hypoglycin. No effects of hypoglycin on the conversion of C14-amino acids into protein or glycogen were demonstrated.

Effect of Adrenalectomy on the Incorporation of Acetate Into Fatty Acids, Cholesterol and Acetoacetic Acid by Rat Liver Slices

1955 ◽  
Vol 184 (1) ◽  
pp. 59-62 ◽  
Author(s):  
W. F. Perry ◽  
Helen F. Bowen
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Rat Liver ◽  
Acid Formation ◽  
Acetoacetic Acid ◽  
Adrenalectomized Animal ◽  
Liver Slices ◽  
Adrenalectomized Rats

The incorporation of C14 acetate into fatty acids, cholesterol, acetoacetic acid and CO2 by liver slices of intact and adrenalectomized rats was studied, the slices being incubated in bicarbonate and phosphate buffers. It was found that in both buffer systems incorporation into fatty acids and cholesterol was depressed while incorporation into acetoacetic acid was unaffected by adrenalectomy. However, total acetoacetic acid formation by the slices tended to be higher in preparations from adrenalectomized animals. The amount of acetate carbon appearing as CO2 was similar with slices from both types of animals. Bicarbonate was found to be a more favorable medium than PO4 for fatty acid formation, while PO4 was the more favorable medium for cholesterogenesis, though the differences between adrenalectomized and intact animals persisted in either buffer. Forced feeding with glucose increased the incorporation of acetate into fat and cholesterol in both buffer systems in adrenalectomized as well as in intact animals. However, the adrenalectomized preparation still incorporated acetate to a lesser extent than the controls. It was concluded that while the depressed incorporation of acetate into fatty acid and cholesterol by adrenalectomized liver slices was consistent with a depressed synthesis of these lipids, there was also the possibility that it reflected an increased turnover of lipids in the liver of the adrenalectomized animal.

EFFECTS OF DIET ON INCORPORATION OF ACETATE-1-C14 INTO CHOLESTEROL BY RAT LIVER SLICES

1960 ◽  
Vol 38 (7) ◽  
pp. 649-656 ◽  
Author(s):  
K. K. Carroll
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Rat Liver ◽  
Liver Cholesterol ◽  
Chow Diet ◽  
Acetate Incorporation ◽  
Test Diet ◽  
Semisynthetic Diet ◽  
Liver Slices ◽  
Fat Soluble Vitamins

The rate of incorporation of acetate-1-C14 into cholesterol by rat liver slices decreased when animals were transferred from a commercial chow diet to semisynthetic diets. A greater decrease was observed when the test diet contained oleic acid or olive oil than when it contained higher homologues of oleic acid, or preparations of cerebrosides. The decrease was not affected by the presence or absence of fat-soluble vitamins in the test diet containing oleic acid. Amphenone B affected acetate incorporation into liver cholesterol differently depending on whether it was fed in a chow diet or a semisynthetic diet. The incorporation of acetate into liver fatty acids of rats fed various diets usually increased or decreased with incorporation into cholesterol but differences between groups were less marked. Incorporation of acetate into cholesterol by intestinal mucosa was relatively insensitive to changes in diet.

EFFECTS OF DIET ON INCORPORATION OF ACETATE-1-C14 INTO CHOLESTEROL BY RAT LIVER SLICES

1960 ◽  
Vol 38 (1) ◽  
pp. 649-656
Author(s):  
K. K. Carroll
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Rat Liver ◽  
Liver Cholesterol ◽  
Chow Diet ◽  
Acetate Incorporation ◽  
Test Diet ◽  
Semisynthetic Diet ◽  
Liver Slices ◽  
Fat Soluble Vitamins

The rate of incorporation of acetate-1-C14 into cholesterol by rat liver slices decreased when animals were transferred from a commercial chow diet to semisynthetic diets. A greater decrease was observed when the test diet contained oleic acid or olive oil than when it contained higher homologues of oleic acid, or preparations of cerebrosides. The decrease was not affected by the presence or absence of fat-soluble vitamins in the test diet containing oleic acid. Amphenone B affected acetate incorporation into liver cholesterol differently depending on whether it was fed in a chow diet or a semisynthetic diet. The incorporation of acetate into liver fatty acids of rats fed various diets usually increased or decreased with incorporation into cholesterol but differences between groups were less marked. Incorporation of acetate into cholesterol by intestinal mucosa was relatively insensitive to changes in diet.

Utilization of fatty acids by rat liver slices as a function of medium concentration

1964 ◽  
Vol 206 (2) ◽  
pp. 345-350 ◽  
Author(s):  
Herbert Rose ◽  
Martha Vaughan ◽  
Daniel Steinberg
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Rat Liver ◽  
Neutral Lipids ◽  
Specific Radioactivity ◽  
Lipid Synthesis ◽  
Normal Liver ◽  
Precursor Pool ◽  
Liver Slices

The rate of incorporation of palmitate-1-C14 into neutral lipids and phospholipids of rat liver slices in vitro and its conversion to C14O2 were shown to increase markedly as the free fatty acid (FFA) concentration of the medium was increased. Incorporation into lipids and conversion to C14O2 proceeded linearly with time over 60 min. The incorporation of glycerol-1,3-C14 into neutral lipids also increased as the FFA concentration of the medium was increased but incorporation into phospholipids was unchanged. It is concluded that high FFA concentrations cause a true increase in rate of neutral lipid synthesis by liver slices. The associated increase in incorporation of labeled palmitate into phospholipids most likely reflects the higher specific radioactivity of the precursor pool of FFA and/or an exchange reaction rather than a true increase in net synthesis. A method for recovering tissue FFA quantitatively is described. Normal liver was found to contain 0.40–0.87 µEq FFA/g wet wt. The composition of this tissue FFA fraction is presented.

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