scholarly journals ELECTRICAL COUPLING BETWEEN FAT CELLS IN NEWT FAT BODY AND MOUSE BROWN FAT

1971 ◽  
Vol 50 (3) ◽  
pp. 795-803 ◽  
Author(s):  
Judson D. Sheridan
Keyword(s):  
Fat Body ◽  
Electrical Coupling ◽  
Intercellular Junctions ◽  
Brown Fat ◽  
Fat Cells ◽  
Newborn Mice ◽  
Low Resistance ◽  
Direct Observations ◽  
White Fat

White fat from the newt, Triturus pyrrhogaster, fat body, and brown fat from the interscapular fat pad of newborn mice have been tested for the presence of low-resistance intercellular junctions. 42 pairs of amphibian fat cells and 15 pairs of mammalian brown fat cells were found to be "electrically coupled." In most of these cases intracellular deposition of a dye, Niagara Sky Blue: 6B, was used to supplement and confirm direct observations of impalements. Coupling was often difficult to find in both preparations, but the mechanical disturbance of the tissue during the preparative procedures may have uncoupled many cells. The fact that, in both types of fat, coupling was observed between cells separated by one or more other cells suggests that coupling may be more widespread in vivo. Electron microscopy (provided by Dr. J. -P. Revel and Mrs. K. Wolken) of the brown fat revealed frequent intercellular junctions resembling "gap junctions" but possibly lacking the substructure usually visible with colloidal lanthanum infiltration. The results are discussed in relation to current ideas about the exchange of regulatory molecules via low-resistance junctions and about the control of brown fat by hormones and nerves.

Burn Injury or Cutaneous Wound Injury to Mice Stimulates Brown Fat but not White Fat Uptake of F18-FDG in Vivo

2006 ◽  
Vol 27 (Supplement) ◽  
pp. S166
Author(s):  
Q Zhang ◽  
E A. Carter ◽  
B Y. Ma ◽  
L J. Mcintosh ◽  
E Cyr ◽  
...  
Keyword(s):  
Burn Injury ◽  
Brown Fat ◽  
Cutaneous Wound ◽  
Fat Uptake ◽  
White Fat

Regional blood flow in rats after a single low-protein, high-carbohydrate test meal

1984 ◽  
Vol 247 (1) ◽  
pp. R160-R166 ◽  
Author(s):  
Z. Glick ◽  
S. J. Wickler ◽  
J. S. Stern ◽  
B. A. Horwitz
Keyword(s):  
Blood Flow ◽  
Test Meal ◽  
Resting State ◽  
Brown Fat ◽  
Blood Flows ◽  
High Carbohydrate ◽  
Low Protein ◽  
Brown Adipose ◽  
White Fat

It was previously observed that a single low-protein, high-carbohydrate test meal results in increased in vitro thermic activity of brown adipose tissue. In the present study, we have examined whether such a meal increases the in vivo thermic activity, estimated from measurement of the rate of blood flow. With radioactively labeled microspheres, blood flows into brown fat and several other tissues were determined in meal-deprived (n = 11) and meal-fed (n = 11) rats. The microspheres were injected into the heart of anesthetized animals about 2-2.5 h after the test meal, one injection in the resting state and one during maximal norepinephrine stimulation. In the resting state, blood flow per gram tissue more than doubled in the brown fat (P less than 0.05) and was increased more than 50% in the heart (P less than 0.01) of the fed group. Blood flows into liver and retroperitoneal white fat were reduced by 40 (P less than 0.01) and 30%, respectively, in the fed group. During norepinephrine infusion, significant meal-associated increases in blood flow were evident only in brown fat (P less than 0.05) and the soleus muscle (P less than 0.05), whereas a significant decrease was observed in the liver (P less than 0.05). No statistically significant meal-associated changes in norepinephrine-stimulated blood flow were found in the other tissues examined (i.e., heart, gastrocnemius, and diaphragm muscles, kidneys, white fat, spleen, and adrenals). Our in vivo data thus support the view that brown fat plays a role in the thermic effect of a meal.

Fluorescence detection of mitochondrial clusters in mammalian white fat cells in vivo

1987 ◽  
Vol 253 (6) ◽  
pp. C783-C791 ◽  
Author(s):  
F. D. DeMartinis ◽  
K. T. Ashkin ◽  
K. T. Lampe
Keyword(s):  
Nerve Fibers ◽  
Epifluorescence Microscopy ◽  
Fat Cells ◽  
Fat Cell ◽  
Physiological Factors ◽  
Cytoplasmic Organization ◽  
Capillary Endothelial Cells ◽  
Mouse Adipocytes ◽  
White Fat

Rhodamine 123 and epifluorescence microscopy revealed a significant portion of the fat cell's mitochondria existed in the form of clusters or aggregates, whereas the remainder were scattered about the cytoplasm. The aggregates were variable in size and number and apparently bore no fixed relationship to the nucleus or to each other. Mitochondrial clusters were seen in vivo in rat and mouse adipocytes of the mesenteric and epididymal depots, in excised tissue pieces of other depots, and in isolated fat cells. Physiological factors investigated such as species type (rat, mouse, rabbit, dog), sex, age, depot location (superficial vs. deep), fat cell size, hypercholesterolemia, and 24-h fasting had no apparent effect on cluster prevalence or size. Similar aggregates were not visible in several cultured cell lines studied nor in various non-fat cells, capillary endothelial cells, or nerve fibers contained within adipose depots examined. These results indicate that mitochondrial clusters exist naturally in mammalian white fat cells and conclude that they represent a form of cytoplasmic organization whose purposes are not well understood.

scholarly journals Adrenergic control of induction of type II iodothyronine 5′-deiodinase activity in cultured mouse brown adipocytes

1993 ◽  
Vol 292 (1) ◽  
pp. 303-308 ◽  
Author(s):  
S Pavelka ◽  
J Hermanská ◽  
M Baudysová ◽  
J Houstĕk
Keyword(s):  
Cyclic Amp ◽  
Time Course ◽  
Brown Fat ◽  
Fat Cells ◽  
Type Ii ◽  
Brown Adipocytes ◽  
Adrenergic Agents ◽  
Adrenergic Control ◽  
Stimulation Of

Iodothyronine 5′-deiodinase (5′D) of mouse brown adipocytes differentiated in cell culture was characterized in detail with respect to the adrenergic control of its biosynthesis. The stimulation of 5′D required mRNA and protein synthesis and was dependent on the stage of differentiation of the cells. The maximum induction was observed around confluence (7-day-old cells), in pre- and post-confluent cells the 5′D activity was significantly less induced. The transient responsiveness of brown fat-cells to the stimulatory effect of adrenergic agents was reflected also in the time course of the induction of 5′D by different concentrations of agonists. The maximum response occurred regularly after an 8 h incubation and implicated a rather fast turnover of the induced enzyme. On the basis of the inhibitory effects of cycloheximide and actinomycin D, the half-life of the induced 5′D and its mRNA were estimated to be 1.5 and 3.3 h respectively. The noradrenaline-induced 5′D activity was shown to be that of the type II enzyme, insensitive to propylthiouracil (PTU). The estimated values of its apparent Km for thyroxine, Km for the co-substrate dithiothreitol, and Vmax. in the presence of 1 mM PTU were 2 nM, 2.6 mM, and 0.1 pmol of I-/h per mg of protein respectively. The 5′D activity was effectively induced by forskolin and dibutyryl cyclic AMP, as well as by isoprenaline, noradrenaline and CGP-12177, but not by phenylephrine, cirazoline or oxymetazoline. This indicates that, contrary to previous observations in vivo, stimulation of 5′D in cultured brown fat-cells involves elevated cyclic AMP levels and is mediated predominantly via beta-receptors, particularly via the so-called beta 3-adrenoceptors.

scholarly journals ELECTROPHYSIOLOGICAL EVIDENCE FOR LOW-RESISTANCE INTERCELLULAR JUNCTIONS IN THE EARLY CHICK EMBRYO

1968 ◽  
Vol 37 (3) ◽  
pp. 650-659 ◽  
Author(s):  
Judson D. Sheridan
Keyword(s):  
Chick Embryo ◽  
Neural Tube ◽  
Electrical Coupling ◽  
Intercellular Junctions ◽  
Neural Plate ◽  
Early Chick Embryo ◽  
Low Resistance ◽  
Electrophysiological Evidence ◽  
Electron Microscopical ◽  
Different Tissues

Electrophysiological evidence is presented for the exchange of small ions directly between cells interiors, i.e. "electrical coupling," in the early chick embryo. Experiments with intracellular marking show that coupling is widespread, occurring between cells in the same tissue, e.g. ectoderm, notochord, neural plate, mesoderm, and Hensen's node, and between cells in different tissues, e.g. notochord to neural plate, notochord to neural tube, notochord to mesoderm. The coupling demonstrates the presence of specialized low-resistance intercellular junctions as found in other embryos and numerous adult tissues. The results are discussed in relation to recent electron microscopical studies of intercellular junctions in the early chick embryo. The function of the electrical coupling in embryogenesis remains unknown, but some possibilities are considered.

CLASSIFICATION OF BENIGN FATTY TUMOURS OF THE UPPER LIMB

Hand Surgery ◽  
2005 ◽  
Vol 10 (01) ◽  
pp. 43-59 ◽  
Author(s):  
M. M. Al-Qattan ◽  
A. M. Al-Lazzam ◽  
A. Al Thunayan ◽  
A. Al Namlah ◽  
S. Mahmoud ◽  
...  
Keyword(s):  
Upper Limb ◽  
Brown Fat ◽  
Fat Cells ◽  
Anatomic Site ◽  
Radiological Features ◽  
White Fat

In this paper, the authors offer a classification of benign fatty tumours of the upper limb. There are three histologically distinct types of fat cells: immature fat cells which give rise to lipoblastomas, mature brown fat cells which give rise to hibernomas and mature white fat cells which give rise to lipomas. Lipomas are the most common and they are sub-classified according to the anatomic site of fat cells into dermal, subcutaneous and sub-fascial lipomas; or tumours directly related to muscle, bone, synovium or nerve. Finally, the authors review 67 patients with benign fatty tumours of the upper limb and provide clinical examples of these tumours including their characteristic histological and radiological features.

Effect in vivo of norepinephrine on the membrane resistance of brown fat cells

1971 ◽  
Vol 27 (12) ◽  
pp. 1419-1421 ◽  
Author(s):  
J. M. Horowitz ◽  
B. A. Horwitz ◽  
R. Em. Smith
Keyword(s):  
Membrane Resistance ◽  
Brown Fat ◽  
Fat Cells

scholarly journals A comparison between the effects of cold exposure in vivo and of noradrenaline in vitro on the metabolism of the brown fat of new-born rabbits

1970 ◽  
Vol 119 (1) ◽  
pp. 103-111 ◽  
Author(s):  
B. L. Knight ◽  
N. B. Myant
Keyword(s):  
Cold Exposure ◽  
Brown Fat ◽  
O2 Consumption ◽  
Adult Rats ◽  
New Born ◽  
Co2 Output ◽  
Cervical Sympathetic ◽  
White Fat

1. Exposure of new-born rabbits to the cold leads to an increase in the incorporation of [14C]glucose into the glycerol of brown-fat triglyceride, but has no effect on [14C]glucose incorporation into triglyceride of white fat or liver. The effect of cold exposure on brown-fat triglyceride is abolished by cutting the cervical sympathetic nerve. 2. Brown fat incorporates very little [14C]glucose into triglyceride fatty acids, either in vivo or in vitro. 3. Noradrenaline added to incubations of brown fat from new-born rabbits stimulates O2 consumption, CO2 output and incorporation of glucose into triglyceride glycerol. The effects of noradrenaline in vitro are therefore consistent with the hypothesis that noradrenaline mediates the response of the brown fat of new-born rabbits to cold exposure. 4. Glycerokinase is present in the brown fat of new-born rabbits, but its activity is much less than that of the glycerokinase in the brown fat of adult rats. 5. Insulin has no effect on O2 consumption, CO2 output or glucose uptake in brown fat of new-born rabbits. 6. It is concluded that the thermogenic response of new-born rabbits to cold exposure is accompanied by a selective acceleration of the triglyceride cycle in brown fat. However, resynthesis of triglyceride would not account for more than 1% of the O2 consumed in vitro by new-born rabbit brown fat in the presence of noradrenaline if respiration remains coupled to phosphorylation.

scholarly journals LOW-RESISTANCE JUNCTIONS BETWEEN CANCER CELLS IN VARIOUS SOLID TUMORS

1970 ◽  
Vol 45 (1) ◽  
pp. 91-99 ◽  
Author(s):  
Judson D. Sheridan
Keyword(s):  
Cancer Cells ◽  
Solid Tumors ◽  
Electrical Coupling ◽  
Inorganic Ions ◽  
Intercellular Junctions ◽  
Sarcoma 180 ◽  
Normal Cells ◽  
Novikoff Hepatoma ◽  
Low Resistance ◽  
Abnormal Distribution

Electrical coupling, which reveals the presence of specialized low-resistance intercellular junctions, has now been found in four types of tumors, Sarcoma 180, Novikoff hepatoma, and Morris hepatomas 3924-A and 7777. Coupled cancer cells were distinguished from coupled normal cells by intracellular marking techniques. Although the evidence suggests that coupling may be extensive in some cases, it is not possible to say that the coupling was normal. In particular, the results do not exclude less obvious defects in the specialized junctions, such as abnormal distribution or decreased permeability to molecules other than small inorganic ions. The results are discussed in relation to previous studies of coupling in Novikoff hepatomas and in cultures of S1801 and II cell lines.

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