Heterogeneous labeling of adipocytes during in vivo-in vitro incubation of epididymal fat pads of aging mice with [1-14C] palmitate

Lipids ◽  
1983 ◽  
Vol 18 (1) ◽  
pp. 25-31 ◽  
Author(s):  
V. Hill ◽  
N. Baker
Keyword(s):  
Epididymal Fat ◽  
In Vitro Incubation ◽  
Fat Pads

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.

The inhibitory effects of some adenosine nucleolipids on the lipolysis in rat epididymal fat pads in vitro

1979 ◽  
Vol 44 (5) ◽  
pp. 1651-1656 ◽  
Author(s):  
Sixtus Hynie ◽  
Jiří Smrt
Keyword(s):  
Fatty Acids ◽  
Cyclic Amp ◽  
Dibutyryl Cyclic Amp ◽  
Inhibitory Effects ◽  
Epididymal Fat ◽  
Fat Pads

3'-Oleolyl-2,3-dihydroxypropyl-AMP, 3'-stearoyl-2,3-dihydroxypropyl-AMP, octadecyl-AMP and palmitamidoethyl-AMP inhibited in comparison with adenosine or fatty acids much stronger the lipolysis in rat epididymal fat pads in vitro stimulated by isoproterenol, theophylline and dibutyryl cyclic AMP. The inhibition of the effects of the two latter drugs suggest that the described effect is caused not only by the inhibition of the cyclic AMP production but also by the inhibition of its effect on the following steps in process of lipolysis.

scholarly journals Effects of PKB/Akt inhibitors on insulin-stimulated lipogenesis and phosphorylation state of lipogenic enzymes in white adipose tissue

2020 ◽  
Vol 477 (8) ◽  
pp. 1373-1389
Author(s):  
Nusrat Hussain ◽  
Sheng-Ju Chuang ◽  
Manuel Johanns ◽  
Didier Vertommen ◽  
Gregory R. Steinberg ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
White Adipose Tissue ◽  
Acute Effects ◽  
Lipogenic Enzymes ◽  
Atp Citrate Lyase ◽  
Phosphorylation State ◽  
Epididymal Fat ◽  
Citrate Lyase ◽  
Fat Pads

We investigated acute effects of two allosteric protein kinase B (PKB) inhibitors, MK-2206 and Akti-1/2, on insulin-stimulated lipogenesis in rat epididymal adipocytes incubated with fructose as carbohydrate substrate. In parallel, the phosphorylation state of lipogenic enzymes in adipocytes and incubated epididymal fat pads was monitored by immunoblotting. Preincubation of rat epididymal adipocytes with PKB inhibitors dose-dependently inhibited the following: insulin-stimulated lipogenesis, increased PKB Ser473 phosphorylation, increased PKB activity and decreased acetyl-CoA carboxylase (ACC) Ser79 phosphorylation. In contrast, the effect of insulin to decrease the phosphorylation of pyruvate dehydrogenase (PDH) at Ser293 and Ser300 was not abolished by PKB inhibition. Insulin treatment also induced ATP-citrate lyase (ACL) Ser454 phosphorylation, but this effect was less sensitive to PKB inhibitors than ACC dephosphorylation by insulin. In incubated rat epididymal fat pads, Akti-1/2 treatment reversed insulin-induced ACC dephosphorylation, while ACL phosphorylation by insulin was maintained. ACL and ACC purified from white adipose tissue were poor substrates for PKBα in vitro. However, effects of wortmannin and torin, along with Akti-1/2 and MK-2206, on recognized PKB target phosphorylation by insulin were similar to their effects on insulin-induced ACL phosphorylation, suggesting that PKB could be the physiological kinase for ACL phosphorylation by insulin. In incubated epididymal fat pads from wild-type versus ACC1/2 S79A/S212A knockin mice, effects of insulin to increase lipogenesis from radioactive fructose or from radioactive acetate were reduced but not abolished. Together, the results support a key role for PKB in mediating insulin-stimulated lipogenesis by decreasing ACC phosphorylation, but not by decreasing PDH phosphorylation.

Adenosine regulates blood flow and glucose uptake in adipose tissue of dogs

1986 ◽  
Vol 250 (6) ◽  
pp. H1127-H1135
Author(s):  
S. E. Martin ◽  
E. L. Bockman
Keyword(s):  
Blood Flow ◽  
Adipose Tissue ◽  
Glucose Uptake ◽  
Indirect Effect ◽  
Glycerol Release ◽  
Anesthetized Dogs ◽  
Tissue Contents ◽  
Fat Pads

Intravenous norepinephrine increases glycerol release and blood flow in adipose tissue. The vasodilation may be an indirect effect of norepinephrine through the production of adenosine. Adenosine increases glucose uptake and inhibits lipolysis in vitro. To test whether adenosine regulates blood flow and/or metabolism in vivo, adenosine deaminase (ADA) was infused intra-arterially into the inguinal fat pads of anesthetized dogs. In unstimulated tissues, ADA (n = 7) significantly increased vascular resistance and significantly decreased glucose uptake compared with the effects of a control (boiled deaminase, n = 6) infusion. ADA completely blocked the norepinephrine-induced vasodilation (n = 6). No potentiation of basal or catecholamine-stimulated lipolysis was observed with ADA. The presence of ADA in the interstitial space was verified by analysis of lymph effluents. Interstitial levels of ADA were inversely correlated with the tissue contents of adenosine. These data support the hypothesis that adenosine is a regulator of blood flow in basal and stimulated adipose tissue. Adenosine also appears to regulate glucose uptake, but not lipolysis, in vivo.

Inhibition of matrix metalloproteinase activity by ACE inhibitors prevents left ventricular remodeling in a rat model of heart failure

2007 ◽  
Vol 292 (6) ◽  
pp. H3057-H3064 ◽  
Author(s):  
Gregory L. Brower ◽  
Scott P. Levick ◽  
Joseph S. Janicki
Keyword(s):  
Heart Failure ◽  
Matrix Metalloproteinase ◽  
Ace Inhibitors ◽  
Left Ventricular ◽  
Av Fistula ◽  
Functional Changes ◽  
In Vitro Incubation ◽  
In Vivo Treatment

Angiotensin-converting enzyme (ACE) inhibitors represent the front-line pharmacological treatment of heart failure, which is characterized by left ventricular (LV) dilatation and inappropriate hypertrophy. The mechanism of action of ACE inhibitors is still unclear, but evidence suggests that they may act by influencing matrix metalloproteinase (MMP) activity. This study sought to determine whether ACE inhibitors can directly regulate MMP activity and whether this results in positive structural and functional adaptations to the heart. To this end, MMP-2 activity in LV tissue extracted from rats with an aortocaval (AV) fistula was assessed by in vitro incubation as well as in vivo treatment with captopril, lisinopril, or quinapril. Furthermore, LV size and function were determined in untreated AV fistula rats, AV fistula rats treated with lisinopril (3, 5, and 8 wk), and age-matched sham-operated controls. In vitro incubation with captopril, lisinopril, or quinapril significantly reduced MMP-2 activity, as did in vivo treatment. This occurred without a reduction in the available pool of MMP-2 protein. Long-term in vivo administration of lisinopril also prevented LV dilatation, attenuated myocardial hypertrophy, and prevented changes in myocardial compliance and contractility. The results herein demonstrate that ACE inhibitors prevent MMP-2 activity and, in so doing, represent a mechanism responsible for preventing the negative structural and functional changes that occur in the rat AV fistula model of heart failure.

THE STIMULATING EFFECTS OF ADRENALINE AND ANTERIOR PITUITARY HORMONES ON THE RELEASE OF FREE FATTY ACIDS FROM ADIPOSE TISSUE

1962 ◽  
Vol 25 (2) ◽  
pp. 189-198 ◽  
Author(s):  
R. M. BUCKLE
Keyword(s):  
Fatty Acids ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
Free Fatty Acids ◽  
Pituitary Hormones ◽  
Thyroid Stimulating Hormone ◽  
Adrenocorticotrophic Hormone ◽  
Fat Pads

SUMMARY The quantity of free fatty acids (FFA) released from rat epididymal fat pads in vitro and their concentration within the tissue were determined. The addition of adrenaline, adrenocorticotrophic hormone (ACTH), thyroid stimulating hormone (TSH) and growth hormone (GH) each increased the release of FFA, and their respective minimum effective concentrations were 0·125, 0·004, 0·5 and 1·25 μg./ml. of medium. In every case, the increased release of FFA was associated with a rise in the quantity present within the pads, and the amount released closely paralleled their concentration within the tissue. It is suggested that the stimulatory effect of all four hormones on the release of FFA from adipose tissue is largely a manifestation of their activity of increasing the concentration of FFA within the cells, and this they do by facilitating the net conversion of storage triglyceride to fatty acid. The significance of the relative activities of the hormones in vitro is discussed and compared with their fatty acid mobilizing effects in vivo.

scholarly journals Autoradiographic demonstration of uptake and retention of 3H-estradiol after in vitro incubation.

1981 ◽  
Vol 29 (11) ◽  
pp. 1316-1321 ◽  
Author(s):  
R H Buell ◽  
G Tremblay
Keyword(s):  
Target Cells ◽  
Regional Variability ◽  
Mouse Uterus ◽  
Tissue Sections ◽  
In Vitro Incubation ◽  
Significant Uptake ◽  
Incubation Method ◽  
Silver Grains

An in vitro incubation method is described for the demonstration of 3H-estradiol in sections of mouse uterus by thaw-mount autoradiography. The method involves the incubation of tissue sections in 5 nM 3H-estradiol with a subsequent 2 hr chase in medium containing 3.5 g% bovine serum albumin. The distribution of the silver grains observed compares favorably to that seen by others with dry-mount autoradiography after in vivo injection. The labeling is inhibited by excess estradiol or diethylstilbesterol, but not by progesterone or hydrocortisone. Its subcellular distribution appears predominantly nuclear in presumptive target cells. Some regional variability in degree of labeling is present throughout the sections, but is far less marked within a given area. Because the observed labeling has been retained during a 2 hr chase and can be inhibited, it is likely to represent physiologically significant uptake and retention of 3H-estradiol in target cells. Preliminary results with human mammary carcinoma suggest this method may be applicable to the investigation of estrogen target cells in human tissue.

Pyruvate kinase from the earthworm Allolobophora calliginosa: modification of the enzyme during anaerobiosis

1991 ◽  
Vol 69 (1) ◽  
pp. 251-254
Author(s):  
Athanasios I. Papadopoulos ◽  
Basile Michaelidis ◽  
Isidoros Beis
Keyword(s):  
Pyruvate Kinase ◽  
Deae Cellulose ◽  
Relative Activity ◽  
The Body ◽  
E Coli ◽  
In Vitro Incubation ◽  
Sigmoidal Kinetics ◽  
Independent Protein

The relative activity of pyruvate kinase from the body-wall muscle of the earthworm Allolobophora calliginosa was found to drop dramatically within 6 h of exposure to N2, whereas the opposite was observed during recovery. Two forms of pyruvate kinase (designated as peak I and peak II) were separated chromatographically on DEAE-cellulose and eluted at 50 and 150 mM of KCl, respectively. They displayed different kinetic behaviour with respect to substrate phosphoenolpyruvate; peak I exhibited Michaelis–Menten kinetics whereas peak II showed sigmoidal kinetics. The ratio of the enzyme units (peak I/peak II) decreased from 3.38 under normoxic conditions to 0.09 under anoxic conditions. In vitro incubation of the aerobic form of pyruvate kinase in the presence of ATP and Mg++ resulted in a reduction of the enzyme activity by 64%, suggesting the presence of an endogenous cyclic-nucleotide-independent protein kinase capable of phosphorylating pyruvate kinase. After in vitro incubation, alkaline phosphatase from E. coli increased the depressed activity of anaerobic pyruvate kinase, indicating that the enzyme molecule is phosphorylated in vivo during exposure to anoxia.

scholarly journals Studies on lipogenesis in vivo. Lipogenesis during extended periods of re-feeding after starvation

1968 ◽  
Vol 106 (2) ◽  
pp. 345-353 ◽  
Author(s):  
G. R. Jansen ◽  
M. E. Zanetti ◽  
C. F. Hutchison
Keyword(s):  
Fatty Acids ◽  
Corn Oil ◽  
Fat Content ◽  
Limited Access ◽  
Epididymal Fat ◽  
Extrahepatic Tissues ◽  
Ad Libitum ◽  
Access To Food ◽  
Fat Pads

1. Lipogenesis was studied in mice re-fed for up to 21 days after starvation. At appropriate times [U−14]glucose was given by stomach tube and incorporation of 14C into various lipid fractions measured. 2. In mice starved for 48hr. and then re-fed for 4 days with a diet containing 1% of corn oil, incorporation of 14C from [U−14C]glucose into liver fatty acids and cholesterol was respectively threefold and eightfold higher than in controls fed ad libitum. The percentages by weight of fatty acids and cholesterol in the liver also increased and reached peaks after 7 days. Both the radioactivity and weights of the fractions returned to control values after 10–14 days' re-feeding. These changes could be diminished by re-feeding the mice with a diet containing 20% of corn oil. Incorporation of 14C from [U−14C]glucose into extrahepatic fatty acids (excluding those of the epididymal fat pads) was not elevated during re-feeding with a diet containing either 1% or 20% of corn oil. However, incorporation of 14C from [U−14C]glucose into the fatty acids of the epididymal fat pads was increased in mice re-fed with either diet, as compared with non-starved controls. 3. Lipogenesis was also studied in mice alternately fed and starved. Mice given a diet containing 1% of corn oil for 6hr./day for 4 weeks lost weight initially and never attained the weight or carcass fat content of controls fed ad libitum. Incorporation of 14C from dietary [U−14C]-glucose into the fatty acids of the epididymal fat pads was elevated threefold in the mice allowed limited access to food, although the incorporation into the remainder of the extrahepatic fatty acids was not different from that found for controls. Mice given a diet containing 20% of corn oil for 6hr./day adapted to the limited feeding regimen quicker and in 4 weeks did attain the weight and carcass fat content of controls. Incorporation of 14C from [U−14C]glucose into the fatty acids of the epididymal fat pads and the remainder of the extrahepatic fatty acids was respectively fivefold and threefold higher than in controls fed ad libitum. 4. The elevation in liver lipogenesis during re-feeding was greatest on a diet containing 1% of corn oil, whereas in extrahepatic tissues the increase in lipogenesis was greater when the mice were re-fed or were allowed limited access to a diet containing 20% of corn oil. These results suggest that the causes of the increased rate of incorporation of 14C from [U−14C]glucose into fatty acids during re-feeding may be different in liver from that in extrahepatic tissues.

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