THE EFFECT OF FASTING ON THE ESTERIFICATION OF PALMITATE BY RAT EPIDIDYMAL ADIPOSE TISSUE IN VITRO

1967 ◽  
Vol 45 (6) ◽  
pp. 965-972 ◽  
Author(s):  
Anna M. Daniel ◽  
David Rubinstein
Keyword(s):  
Adipose Tissue ◽  
Neutral Lipids ◽  
Epididymal Adipose Tissue ◽  
Free Glycerol ◽  
Adipose Tissue In Vitro ◽  
Glucose Incorporation ◽  
Tissue Homogenates ◽  
Hydrolysis Of ◽  
Fat Pads

The effect of 48-h fasting on the in vitro esterification of fatty acids by rat epididymal adipose tissue was investigated. Fat pads from fed and fasted animals were incubated with palmitate-9,10-3H and glucose-U-14C. Fasting diminished the incorporation of both isotopes into glycerides. The decrease in glucose incorporation after fasting was found both in the glycerol and fatty acid moieties. The effect of fasting was not altered by the presence of insulin. Since lipotysis, which is increased after fasting, results in the preferential hydrolysis of newly synthesized triglycerides, the amount of labeled free glycerol after incubation was determined. It was insufficient to account for the decrease in glucose incorporation into lipids following fasting. The decrease in esterification of palmitate-9,10-3H could also be detected in free adipocytes and fat-free homogenates, but to a less extent than in intact tissue. Esterification by adipose-tissue homogenates from fasted animals was diminished in spite of optimum concentrations of substrates and coenzymes. The decrease in esterification was reflected in both neutral lipids and phosphatidic acid.

Brown and white adipose tissue metabolism in cold-exposed rats

1964 ◽  
Vol 207 (4) ◽  
pp. 840-844 ◽  
Author(s):  
G. Steiner ◽  
G. F. Cahill
Keyword(s):  
Adipose Tissue ◽  
Brown Adipose Tissue ◽  
White Adipose Tissue ◽  
Neutral Lipids ◽  
Adipose Tissue Metabolism ◽  
Epididymal Fat ◽  
Brown Adipose ◽  
Fat Pads

Brown and white adipose tissue from rats exposed to 5 C for 9 days has been studied with reference to its composition and handling of glucose-U-C14 in vivo and in vitro. Brown adipose tissue from cold-exposed rats demonstrated a decreased lipid content per milligram nitrogen, due mainly to decreased amounts of neutral lipid with little change in phospholipid. The incorporation of glucose into neutral lipids, glyceride glycerol, and fatty acids was increased in vivo and in vitro. There was increased incorporation into CO2 in vitro and there was no change in glucose conversion to phospholipid in vivo. No changes in any of these were noted in epididymal fat pads. These findings suggest that cold exposure leads to alterations in carbohydrate metabolism and lipogenesis in brown adipose tissue but not in epididymal fat pads. The possible role in thermogenesis is discussed.

ESTERIFICATION OF INTRA- AND EXTRA-CELLULAR FREE FATTY ACIDS BY RAT ADIPOSE TISSUE

1965 ◽  
Vol 43 (6) ◽  
pp. 635-645 ◽  
Author(s):  
David Rubinstein ◽  
Anna M. Daniel ◽  
Lydia Lechter ◽  
John C. Beck
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Incubation Medium ◽  
Neutral Lipids ◽  
Long Chain Fatty Acids ◽  
Adipose Tissue In Vitro ◽  
Rat Adipose Tissue ◽  
Glycerol Esterification ◽  
Long Chain

The esterification of intracellular and extracellular FFA by rat adipose tissue in vitro was investigated. The rate of incorporation of FFA into neutral lipids was proportional to the FFA concentration in the incubation medium. Both in the presence and absence of a lipolytic agent (epinephrine), heptadecanoate-1-C14, which is not specifically diluted by tissue fatty acids, was esterified in the same manner as palmitate-9,10-H3. Stearate, palmitate, and oleate were esterified at similar rates by adipose tissue taken from fed animals and incubated with glucose. The rate of esterification of one fatty acid was not significantly affected by the presence of another. Similar results were obtained when tissues were taken from fasted animals and incubated in the absence of glucose, except that the overall rate of esterification was diminished and FFA accumulated in the tissue. It is concluded that long-chain fatty acids do not compete for esterification or entry into the adipose tissue cell.In some experiments tissue FFA esterification was studied by measuring the incorporation of glucose-U-C14 carbons into glyceride–glycerol. Esterification, assayed in this manner, increased when albumin was present in the incubation medium and allowed FFA to diffuse from the tissue. However, pre-incubation of adipose tissue in medium containing labelled FFA indicates that much of the intracellular FFA may be esterified without its mixing with the extracellular FFA pool.

scholarly journals Degradation of insulin in vitro by liver and epididymal adipose tissue from obese–hyperglycaemic mice

1968 ◽  
Vol 106 (2) ◽  
pp. 543-547 ◽  
Author(s):  
Sighild Westman
Keyword(s):  
Adipose Tissue ◽  
Degradation Products ◽  
Serum Insulin ◽  
Epididymal Adipose Tissue ◽  
Insulin Degradation ◽  
Fat Depots ◽  
Insulin Tolerance ◽  
Tissue Homogenates ◽  
Assay Conditions

The insulin-degrading activity of liver supernatants and epididymal adipose-tissue homogenates from genetically obese–hyperglycaemic mice (ob ob) and their lean litter mates was studied by measurement of radioactive trichloroacetic acid-soluble degradation products of the insulin molecule. Optimum assay conditions for the decomposition of the hormone were devised. The properties of the degrading activity suggested the presence of enzymic insulin destruction in both the liver and epididymal adipose tissue. There was no difference in insulin degradation in liver samples from obese and lean mice when the results were related to the protein content of the supernatants. The epididymal adipose-tissue homogenates from obese mice displayed about eightfold higher degrading activity per unit of protein than did homogenates from lean animals. The physiological significance of this finding is discussed in the light of the increased fat depots, hyperphagia, raised serum insulin concentrations and increased insulin tolerance previously recorded in this strain of mice.

Cold effects in rat: plasma and adipose tissue free fatty acids and adipose lipase

1963 ◽  
Vol 204 (1) ◽  
pp. 157-164 ◽  
Author(s):  
Samuel Mallov
Keyword(s):  
Adipose Tissue ◽  
Lipolytic Activity ◽  
Rat Plasma ◽  
Epididymal Adipose Tissue ◽  
Albino Rats ◽  
Adipose Tissues ◽  
Tissue Sections ◽  
Tissue Homogenates ◽  
Increased Activity

Male albino rats were exposed to cold or kept at room temperature for 1–24 hr. Plasmas and epididymal adipose tissues were analyzed for free fatty acid (FFA) concentrations and lipolytic activities of intact sections and homogenates, as well as release of FFA by adipose tissues, determined in vitro. Plasmas of rats exposed to cold had significantly higher FFA levels than did plasmas from controls, and intact epididymal adipose tissue sections from cold-exposed rats had higher FFA concentrations, released greater quantities of FFA, and manifested higher lipase activities in the presence of activated triglyceride substrate than did sections from control rats. Exposure to cold may increase FFA mobilization from adipose tissues as a result of enhanced lipolytic activity, due to lipase activation by catecholamines released from adrenals and sympathetic nerve endings. The enzyme activated did not possess several of the properties characteristic of lipoprotein lipase. Tissue homogenates did not manifest increased activity after cold exposure, possibly as a result of activation by the homogenization process itself.

HORMONAL REGULATION OF GLUCOSE METABOLISM IN ADIPOSE TISSUE IN VITRO

1965 ◽  
Vol 131 (1 Adipose Tissu) ◽  
pp. 43-58 ◽  
Author(s):  
Bernard R. Landau ◽  
Joseph Katz ◽  
Glenn E. Bartsch ◽  
Lawrence W. White ◽  
Hollis R. Williams
Keyword(s):  
Adipose Tissue ◽  
Glucose Metabolism ◽  
Hormonal Regulation ◽  
Adipose Tissue In Vitro

Hepatocyte differentiation of mesenchymal stem cells from human adipose tissue in vitro promotes hepatic integration in vivo

Gut ◽  
2008 ◽  
Vol 58 (4) ◽  
pp. 570-581 ◽  
Author(s):  
H Aurich ◽  
M Sgodda ◽  
P Kaltwasser ◽  
M Vetter ◽  
A Weise ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Adipose Tissue ◽  
Human Adipose Tissue ◽  
Hepatocyte Differentiation ◽  
Adipose Tissue In Vitro
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