Free Fat Cells Research Articles

Use of restonTM foam in liposuction

Use of Reston foam along with a pressure garment after liposuction results in three salutary effects: less waviness in the skin surface, a more comfortable recovery, and less blood loss and ecchymoses. Free fat cells are thought to be redistributed evenly by the pressure of the foam plus the pressure garment. The result is a smoother skin surface with less waviness. Reston foam is also comfortable under the pressure garment and there is less immediate postoperative tenderness. In addition, the use of the foam, in conjunction with the pressure garment, results in less postoperative bleeding and bruising. Consequently, there is also a decrease in the amount of postoperative fall in hematocrit. Since there is less of a drop in hematocrit and hemoglobin, there is also less postoperative anemia. The mechanism involved in the reduction in blood loss is thought to be a combination of overcoming capillary pressure and stabilization of the skin and subsurface blood vessels.

Equivalent In Vivo Biological Activity of Insulin Analogues and Human Insulin Despite Different In Vitro Potencies

In vivo biological potency of two human insulin analogues, AspB9,GluB27 insulin and AspB10 insulin with low and high affinity to the insulin receptor, respectively, was assessed by intravenous infusion of equimolar amounts in pigs, with the euglycemic clamp technique. Human insulin and the low- and high-affinity analogues showed equivalent glucose utilization rates in the steady state (mean +/- SE 14.7 +/- 1.4, 12.7 +/- 1.5, and 12.2 +/- 1.2 mg.kg-1.min-1, respectively; n = 7). The corresponding plasma insulin levels, however, were markedly different (329 +/- 25 and 856 +/- 46 pM, P less than 0.05; 197 +/- 19 pM, P less than 0.05). There was an inverse relationship between the insulin levels and the in vitro activities measured by binding to human hepatoma cells (HepG2; 100, 20, and 308%) or by incorporation of glucose into lipids in mouse free fat cells (100, 31, and 207%). The total amount of glucose infused during and after insulin infusion was equal for the three insulins, whereas glucose utilization as a function of time was somewhat different. By describing the individual plasma concentration courses with an open two-compartment model with elimination from the receptor compartment, the time courses for binding and elimination of the three insulins in the receptor compartment were estimated. The effect seems closely linked to the elimination of insulin from the receptors rather than to the amount of insulin bound to the receptors. In conclusion, the total effect of equimolar amounts of human insulin and the two insulin analogues on glucose utilization is equal regardless of the different receptor affinities of the insulins.

Body Contouring: Suction-Assisted Lipolysis and Ft Transplantation Techniques

Suction lipolysis is a technique of blunt aspiration of fat that allows contouring and shaping of fatty distributions in a variety of areas of the body. Sufficient experience with the technique exists so that it may be considered an acceptable and safe procedure in the armamentarium of the plastic and reconstructive surgeon. It is a basically low-risk surgical procedure that usually is performed on an outpatient basis, and its results are permanent. Autologous fat transplantation or microlipoinjection is a recent outgrowth of liposuction surgery. It involves gentle aspiration of free fat cells from one area of the body and reinjection of these cells into other areas to accomplish either cosmetic or reconstructive soft-tissue augmentation. It is still investigational in nature, and accurate, reproducible data demonstrating its prolonged efficacy are not yet available.

Study on hypoglycemic effects of muscles of pig (Sus scrofa), chicken (Gallus domesticus) and mackerel (Scomber japonicus).

The hypoglycemic activity of extracts from muscles of pigs (Sus scrofa; P), chickens (Gallus domesticus; C) and mackerel (Scomber japonicus; M) was examined. P exhibited an insulin-like activity on conversion of glucose to total lipids in rat free fat cells and an insulin secretion-promoting effect on perfused rat pancreas. C showed an insulin-like activity, an insulin secretion-promoting effect and an inhibitory effect on hepatic glycogenolysis. M proved to have a weak insulin-like activity, and a weak insulin secretion-promoting effect, but its inhibitory effect on hepatic glycogenolysis was strong.After intraperioneal administration of P, C and M, the blood glucose levels decreased in both normal mice and alloxan-induced diabetic mice.

Structure-function relationships in glucagon. Re-evaluation of glucagon-(1-21).

Glucagon-(1-21) was prepared fully synthetically as well as by carboxypeptidase A digestion of natural porcine glucagon. Neither of the two preparations had glucagon agonistic effects with regard to receptor binding or adenylate cyclase activation in purified rat liver plasma membranes. Nor did these preparations contain lipolytic activity in isolated free fat cells. A preliminary batch of glucagon-(1-21) prepared by carboxypeptidase A digestion did, however, contain 1-2% glucagon bioactivity. This activity was separated from glucagon-(1-21) by high-performance liquid chromatography and quantitatively recovered in four minor hind peaks which eluted close to but not in a position identical to the elution position of native glucagon.

The stimulating effect of 3′,5′-(cyclic)adenosine monophosphate and lipolytic hormones on [formula omitted] transport and 45Ca 2+ release in adipocytes and skeletal muscle of the rat

(1) In order to assess the possible role of 3′,5′-(cyclic)adenosine monophosphate (cAMP) in the control of glucose transport, the effect of the nucleotide or agents known to increase its intracellular concentration on sugar transport or 45Ca 2+ washout were characterized in epididymal fat pads, free fat cells and soleus muscles of the rat. (2) When added to the incubation medium, cAMP (0.1–2.0 mM) stimulated 3-O-[ 14 C] methylglucose washout from fat pads. This effect was abolished by cytochalasin B, and additive to that induced by submaximal (10–25 μU/ml), but not by supramaximal (10 mU/ml) concentrations of insulin. (3) cAMP (2 mM) stimulated the conversion of [U- 14C]glucose into CO 2 and triacylglycerols. This effect was additive to that of insulin (100 μU/ml). (4) ACTH, glucagon, adrenaline, noradrenaline and salbutamol, which are all known to increase the cAMP content of adipose tissue, stimulated the washout of 3-O-[ 14 C] methylglucose and 45Ca 2+ from preloaded fat pads. The fractional losses of the two isotopes were significantly correlated ( P < 0.001, r = 0.73). (5) In free fat cells, adrenaline (10 −6 M) and salbutamol (10 −5 M) stimulated the uptake of 3-O-[ 14 C] methylglucose , and salbutamol (10 −5 M) did not interfere with the stimulating effect of insulin (25 μU/ml) on sugar uptake. (6) In rat soleus muscles, adrenaline and salbutamol produced a dose-dependent stimulation of the washout of 3-O-[ 14 C] methylglucose and 45Ca 2+. The effect of adrenaline on sugar efflux was abolished by propranolol. (7) It is concluded that the activation of the glucose transport system by insulin is unlikely to be mediated by a drop in the cellular concentration of cAMP. An increase in cAMP brought about by β-adrenoceptor agonists or lipolytic hormones may induce a mobilization of calcium ions from cellular pools into the cytoplasm, which in turn leads to the activation of the glucose transport system demonstrated in the present as well as in several earlier studies.

Glucagon: structure-function relationships investigated by sequence deletions.

A series of glucagon analogues, des-(1-4)-glucagon, des-(5-9)-glucagon, des-(10-15)-glucagon, des-(16-21)-glucagon, des-(22-26)-glucagon and des-(27-29)-glucagon, were prepared by condensation of synthetic fragments and characterized biologically and immunologically. Fully synthetic glucagon was also characterized. The potencies with regard to glucagon receptor binding in purified rat liver plasma membranes were, in decreasing order: synthetic glucagon 108%, des-(1-4)-glucagon 5.7%, des-(27-29)-glucagon 0.92%, des-(5-9)-glucagon 0.47%, des-(10-15)-glucagon 0.0028%, des-(16-21)-glucagon 0.0017% and des-(22-26)-glucagon 0.00060% relative to that of natural porcine glucagon. Des-(27-29)-glucagon was the only analogue that activated the adenylate cyclase in rat liver plasma membranes or stimulated the lipolysis in isolated free fat cells from rat epididymal fat pad. The potencies were 0.16% and 0.20% of that of glucagon, respectively. Des-(1-4)-glucagon was a glucagon antagonist in the adenylate cyclase assay. The immunoreactivities of the glucagon analogues were determined with two commonly used anti-glucagon sera, K 5563 and K 4023, directed towards the C-terminus and some segment in the sequence 2-23, respectively. In the K 5563 assay, des-(27-29)-glucagon and des-(22-26)-glucagon had potencies of 0.0009% and less than 0.09% of that of glucagon, respectively. The remaining analogues had potencies varying from 45% to 141% of that of glucagon. In the K 4023 assay, the analogues showed a non-linear dilution effect. The combined results indicate a partition within the glucagon molecule with regard to receptor binding and adenylate cyclase activation. The region 10-26 appears to be the most important for receptor binding, whereas 1-4 is essential for adenylate cyclase activation. The C-terminal segment 27-29 is important for the maintenance of full receptor binding but non-essential for adenylate cyclase activation.

Release of newly synthesized squalene, methyl sterols and cholesterol from human adipocytes in the presence of lipoproteins.

Upon incubation of free fat cells for 3 h with labelled mevalonate, more than 90% of the radioactivity of the non-saponifiable material was found in the squalene fraction and less than 10% in the methyl sterol and cholesterol fractions. About 25, 30 and 65% of the cholesterol counts were found respectively in VLDL, LDL, or HDL added to the medium while none of the newly synthesized squalene was released into the lipoproteins. The results indicate that adipose tissue squalene can originate from local synthesis. It is not released from the cells into the medium, but can contribute to local cholesterol synthesis in both rapidly and slowly exchangeable cholesterol pools of adipose tissue.

The effect of diet fat on rat adipocyte glucose transport.

Rats were fed either a high fat diet (67% of calories as lard) or high glucose diet (67% of calories as glucose) for 7-8 days. Basal and insulin stimulated net uptake of D glucose (D-L) and 2 deoxy D glucose uptake by free fat cells of fat rats were depressed. Net transport of D glucose (D-L) by purified adipocyte plasma membranes of fat red rats was also diminished. Incubation of fat cells from glucose fed rats with insulin before homogenization for membrane preparation increased net D glucose transport by subsequently purified membranes in two experiments to a greater extent than in similar preparations from rat fed rats. These experiments suggest that fat feeding modifies the plasma membranes of fat cells so that both glucose transport and the stimulatory effect of insulin on the process are decreased.

Relationships between the exchange of calcium and phosphate in isolated fat-cells.

The uptake and the washout of 45Ca2+ and 32Pi is described in free fat-cells and whole epididymal fat-pads from fed rats. 2. In isolated fat-cells, the uptake of 45Ca2+ proceeds with an initial rapid phase of about 1 min duration, followed by a slower subsequent accumulation. In contrast with the rapid phase, the slow phase is inhibited by 2,4-dinitrophenol, warfarin, oligomycin and verapamil, shows saturation, and presumably represents transport across the plasma membrane. 3. The washout of 45Ca2+ from preloaded cells consists of a rapid (1 min) initial phase and a slow phase which is non-monoexponential, suggesting that the radioactive isotope is released from several cellular pools. 4. When Pi is omitted from the incubation medium, the slow phase of 45Ca uptake is almost abolished, and the washout of 45Ca from preloaded fat-cells is markedly accelerated. At elevated extracellular concentrations of Pi (2,4-6.2mM), the uptake of 45Ca is stimulated by 2-10-fold, and the release of the radioactive isotope from preloaded cells is inhibited. In whole epididymal fat-pads, variations in the extracellular concentration of Pi have no detectable effect on the uptake or the washout of 45Ca. 5. In isolated fat-cells, the accumulation of 32Pi is inhibited by 2,4-dinitrophenol or the omission of glucose from the incubation medium. In a Ca2+-depleted buffer, the uptake of 32Pi is diminished, and hyperosmolarity, which stimulates 45Ca uptake, also accelerates the accumulation of 32Pi. 6. It is concluded that in free fat-cells, the uptake and release of Ca2+ and Pi take place by closely interrelated processes, which are dependent on mitochondrial energy production.

A colorimetric method for the determination of deoxyribonucleic acid in adipose tissue

A method is described for measuring the deoxyribonucleic acid (DNA) content of small samples of adipose tissue or free fat cells. Lipids and acid-soluble nucleotides are first removed by extraction with a cold diethyl ether-ethanol mixture containing 10 per cent. m/V of trichloroacetic acid. DNA is then measured by hydrolysing the nucleoprotein residue in a 5 per cent. solution of trichloroacetic acid at 90 °C for 20 min, followed by treatment with p-nitro-phenylhydrazine and measurement of the hydrazone at 560 nm.

Effects of bovine growth hormone preparations, fragments of growth hormone and pituitary anti-insulin peptide on lipolysis and glucose metabolism of isolated fat cells and adipose tissue.

The effects on rat fat cells and adipose tissue of a bovine adenohypophysial anti-insulin peptide (AIP) were compared to those of various bovine growth hormone preparations. The lipolytic activity of AIP was about 1–2% that of growth hormone on a weight basis. The increase in lipolysis seen with AIP was blocked by cycloheximide. AIP did not alter basal glucose oxidation in fat cells but slightly increased basal glucose oxidation in adipose tissue. AIP also did not inhibit the insulin stimulation of glucose oxidation in free fat cells or adipose tissue. Growth hormone inhibited the increase in glucose oxidation due to insulin but this effect was dependent on lipolysis. Dexamethasone markedly inhibited insulin-stimulated glucose oxidation despite its failure to activate lipolysis. In the presence of dexamethasone the increase in lipolysis due to growth hormone was enhanced. The lipolytic activity of highly purified bovine growth hormone preparations was greater than that of the NIH preparation. The fragment...

Ouabain binding and Na +K + transport in rat muscle cells and adipocytes

1. 1. The accumulation and the release of [ 3H]ouabain has been characterized in isolated intact soleus muscles and free fat cells of the rat. The number of ouabain-binding sites was determined and compared with the rates of active Na +K + transport. 2. 2. In soleus muscle [ 3H]ouabain is bound to the surface of the plasma membrane by a reversible and saturable process, which is inhibited by K +, Li +, 2,4-dinitrophenol, the omission of Na + or the addition of digoxin. 3. 3. The release of [ 3H]ouabain from preloaded muscles is accelerated by K +, 2,4-dinitrophenol and unlabelled ouabain or digoxin, presumably becuase of diminished binding of the glycoside. 4. 4. Under steady-state conditions for ouabain binding a kinetic analysis indicates that soleus muscles contain 7.2 · 10 −1 moles binding sites per g wet wt or 3350 per μm 2 of sarcolemma surface area. An apparent dissociation constant of 2.1 · 10 −7 M was found. 5. 5. Measurement of 22Na efflux and 42K influx under basal conditions indicate that the number of Na + and K + transported per ouabain-binding site correspond to respectively 500 and 325 per min. 6. 6. In isolated fat cells ouabain binding showed qualitatively the same characteristics as in soleus muscle, although the rate was considerably faster and the affinity higher (apparent dissociation constant: 1.7 · 10 −8 M. 7. 7. The fat cells were estimated to contain 2.0 · 10 −11 moles ouabain-binding sites per ml of cells or 66 per μm 2 of plasma-membrane surface. The ouabain-sensitive component of 42K influx corresponds to 3450 ions per site per min. 8. 8. It is concluded that in intact muscle cells and adipocytes, which constitutes the major portion of total body weight in mammals, the binding of ouabain is qualitatively closely similar to that described in microsomal Na + + K +- activated ATPase.

Growth and lipolysis of rat adipose tissue: effect of age, body weight, and food intake

The purpose of the present work was to study age- and weight-controlled rats to determine which is the primary factor in reducing the lipolytic response of free fat cells and which has the greater effect on the ratio of fat cells to nonfat cells in adipose tissue. The method for estimating fat cell and nonfat cell numbers is based on the analysis of adipose tissue and fat cell DNA and lipid. In adequately fed rats, epididymal adipocyte hyperplasia is complete between 9 and 14 wk of age. Chronic underfeeding delays, but does not eliminate, normal fat cell hyperplasia and is accompanied by a net loss in the nonfat cell population. During 9-14 wk of age, rat epididymal adipose tissue enlarges mainly through adipocyte hypertrophy. Total fat cells from the epididymal adipose tissue of control rats represent only 20-23% of the total cell population. Chronic underfeeding increases the percentage of fat cells in the fat pad from 23 to 28%. Noradrenaline-stimulated lipolysis is proportional to fat cell numbers but is inhibited when fat cell lipid increases to over 80% of fat pad wet weight. Rat age is apparently not primarily responsible for the decreased noradrenaline-stimulated lipolysis in fat cells of 350-g rats in vitro.

Preparation and properties of plasma membrane and endoplasmic reticulum fragments from isolated rat fat cells

1. 1. Plasma membrane and endoplasmic reticulum of free fat cells were isolated in high yield as a mixed microsomal fraction by sucrose gradient centrifugation. 2. 2. The semipermeable behavior of these particles was explored by observing shifts in isopycnic density in continuous polymer (Dextran) gradients over a range of pH and ionic conditions. 3. 3. Using a discontinuous Dextran gradient, a plasma membrane fraction was partially purified. The plasma membrane fraction showed a 12–16-fold enrichment of 5′-nucleotidase over the homogenate. Na +-K +-stimulated ATPase was recovered in highest specific activity in this fraction. Mitochondrial contamination was 3% where endoplasmic reticulum contamination was 27%. 4. 4. A sensitive radioassay for 5′-nucleotidase is described.

A mechanism for hormonal activation of lipolysis and respiration in free brown fat cells.

AbstractFree brown fat cells were obtained by digestion of minced brown adipose tissue with bacterial collagenase. Electron micrographs have shown many mitochondria with tightly packed cristae in free brown fat cells. Lipolysis was activated in free brown fat cells was lipolysis accompanied by a marked stimulation of respiration. Insulin inhibits the catecholamine‐induced respiration in the complete absence of glucose. Catecholamines, theophylline and dibutyryl 3′,5′‐AMP all appear to activate lipolysis and respiration by a process dependent upon energy derived from mitochondrial oxidative phosphorylation. Uncoupling agents such asm‐chlorocarbonyl cyanide phenylhydrazone stimulated respiration. The addition of oligomycin prior to that of catecholamine inhibited the increase in respiration to a much greater extent than if it was added after the catecholamine. The increase in respiration due to lipolytic agents appears to be the result of increased free fatty acid release mediated through activation of lipolysis by cyclic 3′,5′‐AMP, since the addition of octanoate or palmitate to brown fat cells mimicked the effects of lipolytic agents on respiration. The activation of energy metabolism may be the result of a large increase in the energy‐dependent cyclic transport of K+, as a result of alterations in the mitochondrial membrane by free fatty acids. This hypothesis is based on the following findings. The activation of respiration by fatty acids or lipolytic agents was dependent upon the presence of K+ in the medium. The addition of K+, Rb+ or Cs+, but not NH4+, to fat cells isolated and incubated in K+‐free buffer restored the ability of lipolytic agents to increase respiration. Valinomycin, an antibiotic which stimulates uptake of K+ by mitochondria and increases the permeability of lipid membranes to K+, was a potent stimulator of respiration in free brown fat cells in the presence of K+. The stimulation of respiration by theophylline or valinomycin was blocked by nigericin which also increases the K+ permeability of membranes but blocks the uptake of K+ by mitochondria. The lipolytic action of theophylline was virtually unaffected by K+ or nigericin.

Amino acid incorporation by a cell-free preparation from rat adipose tissue. Effects of fasting.

Ribosomes were isolated from a postmitochondrial, detergent-treated supernatant fraction prepared either from adipose tissue passed through a tissue press, or from a collection of free fat cells. Optimum conditions for incorporation were established and the kinetics of the system denned with and without artificial messenger RNA. Studies were performed on ribosomes isolated from fed, 24-h fasted, and 48-h fasted animals. There was a progressive reduction in yield and activity (per milligram ribosomal RNA) of ribosomal material recovered from animals fasted up to 48 h. In the presence of poly-U, incorporation by ribosomes from fasted animals returned towards but did not reach the fed level. This return was less complete with ribosomes from 48-h than from 24-h fasted groups although as fasting proceeded, the percentage stimulation produced by poly-U progressively increased. Sucrose density gradient analysis revealed a greater proportion of light ribosome species and a smaller proportion of polysomes in fasted than in fed animals. These results suggest that fasting, in addition to producing a progressive reduction in ribosomal yield, also caused an early loss of messenger RNA or messenger function and later an alteration of ribosome function. The effect of fasting on messenger function could not be explained by alterations in ribonuclease activity.

Lipolytic activity of a peptide fragment of porcine secretin.

Synthetic porcine secretin, a peptide chain of 27 amino acids, accelerates li poly sis in rat and mouse fat cells. Six synthetic fragments of the porcine secretin molecule have now been assayed for lipolytic activity on free fat cells of the rat: peptides 23–27, 14–27, 9–27, 5–27, 5–14 and 1–14. Only peptide 1–14 is active; its minimal effective dose, 1 μg/ml, is 100 × greater on a weight basis and 200 × greater on amolar basis than that of secretin itself in the same assay system. It is concluded that the lipolytic property of secretin resides in the NH2- terminal half of the hormone molecule, 1–14; that sequence 1–4 plays an essential role in the activity of 1–14; and that 15–27, either in whole or in part, enhances the effect of the active region 1–14. (Endocrinology 85: 610,1969)

Responsiveness to Lipolytic Hormones, and Inactivation of Adrenocorticotropin, by Adipose Tissue Slices and Free Fat Cells from Different Mammalian Species

The adipose tissues of rat, hamster and guinea pig are known to differ from each other in capacity to respond to the lipolytic action of adrenocorticotropin (ACTH), β-melanocyte-stimulating hormone (β-MSH), thyroidstimulating hormone (TSH), glucagon and epinephrine, and in capacity of the homogenized tissue, to destroy the lipolytic activity of ACTH and other lipolytic pituitary peptides. In order to learn whether these species differences reside in the fat cells, or in other components of the adipose tissue, (a) adipose tissue slices and free fat cells (prepared by the collagenase technique of Rodbell) from the same rat, hamster or guinea pig were incubated with ACTH, β-MSH, TSH, glucagon or epinephrine, and the lipolytic response was measured; (b) aqueous homogenates of adipose tissue and free fat cells from the same rat or hamster were incubated with ACTH and the effect of the incubation on the hormone’s lipolytic activity was measured. The data show that, in all 15 instances tested, the free fat cells...

Lipolytic activity of synthetic porcine secretin.

Synthetic porcine secretin is a potent lipolytic agent on the adipose tissue of the rat and on the free fat cells of the mouse. The minimal effective dose is 0.1 μg/ml for the rat epididymal adipose tissue slice and 0.001 μg/ml for the free fat cells (mesenteric + perirenal) of the mouse. Secretin has no lipolytic effect on the adipose tissue of hamster, guinea pig, rabbit or pigeon. Bovine glucagon, which is similar in structure to porcine secretin, is active on adipose tissue or free fat cells of rat, mouse, guinea pig and pigeon, and inactive on adipose tissue of hamster and rabbit. (Endocrinology 85: 214, 1969)