Adipose Tissue In Dogs Research Articles

Content of fatty acids in lipids of adipose derived mesenchymal stem cells

The content of fatty acids in the lipids of mesenchymal stem cells of dog adipose tissue culture was studied. Mesenchymal stem cells of dog adipose tissue culture were obtained by culturing the primary material in a CO2 incubator with a content of 5 % CO2, at a temperature of 37 °C in DMEM medium with the addition of 10–15 % fetal bovine serum and 1 % antibiotic-antimycotic. When the confluency of the monolayer reached 70–80 %, the cells were transferred to a suspension and subcultivated in order to reduce the heterogeneity of the culture and obtain a sufficient amount of biological material. The lipids of the obtained stem cells were analyzed for the content of fatty acids by the method of thin-layer gas-liquid chromatography. Determination of the content of lipids of fatty acids in FSK of a cat was carried out by the Folch method. A mixture of fatty acid methyl esters was analyzed on a Trace GC Ultra gas chromatograph with a flame ionization detector on a capillary column SPTM –2560, 100 m x 0.25 mm ID, 0.20 μm film (Supelco). Identification of fatty acids was carried out using a standard sample of Supelco 37 Сomponent FAME Mix. Quantitative assessment of the LC spectrum was carried out by the method of normalization of the peak planes of methylated LC derivatives and their content was determined as a percentage of the total content of all LC. The conducted study of the content of fatty acids in lipids made it possible to reveal certain features of the lipid metabolism of mesenchymal stem cells cultured in dog adipose tissue. A high content of oleic acid, characteristic of cells resistant to apoptosis and with high proliferative potential, was determined; a high ratio of unsaturated linoleic to saturated stearic acid (С18:1/С18.0), which reflects the high activity of the stearoyl-coenzyme-desaturase enzyme and, indirectly, the active state of the Wnt/β-catenin signaling pathway; inability to lengthen the chain of saturated fatty acids; lack or low activity of de novo synthesis of omega-6 polyunsaturated fatty acids. 18 fatty acids were found in the composition of lipids of fetal stem cells of a cat, of the saturated ones - the most palmitic acid (33.70 ± 0.02 %), of the monounsaturated ones – oleic acid (21.63 ± 0.03 %), of the polyunsaturated ones – linoleic acid (6.45 ± 0.07 %). The least amount of cis-,11,14-eicosadienoic acid (0.04 ± 0.01 %) was found in the composition of cell lipids. The total amount of saturated fatty acids in dog mesenchymal stem cell lipids was 65.65 ± 0.02 %), unsaturated fatty acids – 34.35 ± 0.02 %. Monoene fatty acids were determined in the amount of 24.46 ± 0.02 %, and polyene – 9.89 ± 0.02 %. The ratio index of polyunsaturated fatty acids ω 3 to ω 6 is 0.40. Lipids of mesenchymal stem cells of adipose tissue culture were characterized by a lower content of monoene unsaturated fatty acids 24.46 ± 0.02; (P < 0.05), with a higher content of ω3 fatty acids 3.04 ± 0.02 %; (P < 0.05), with a lower content of ω6 fatty acids 6.86 ± 0.02 %; (P < 0.05) in contrast to lipids of red bone marrow stem cells.

Tratamento de trombocitopenia imunomediada crônica com células-tronco mesenquimais em cão - relato de caso

ABSTRACT Immunomediated thrombocytopenia is a systemic metabolic disorder in which the platelet count falls below reference values, as the patient's immune system destroys them. The main clinical signs in thrombocytopenia are petechial, hemorrhages, ecchymoses and suffusions. Hematomas can also occur in coagulation disorders. The diagnosis is based on clinical findings and hematological examinations. The treatment consists of the use of corticosteroids and immunosuppressants, delaying cell destruction, and may last for months, not always obtaining a cure for the disease. The present work reports the use of therapy with allogeneic mesenchymal stem cells, derived from the adipose tissue of dogs, for the treatment of chronic immunomediated thrombocytopenia, with an evolution of more than one year, in a Pinscher dog. The alternative treatment showed a good evolution, keeping platelets within the reference values during the treatment, giving the patient quality of life and removing the need for continuous medication for homeostasis after treatment.

Effects of Intra-Articular Autologous Adipose Micrograft for the Treatment of Osteoarthritis in Dogs: A Prospective, Randomized, Controlled Study.

Simple SummaryOsteoarthritis (OA) is a very common musculoskeletal condition that affects dogs, as well as humans and other species, and causes pain, lameness, and disability. Since therapy is not always effective and is definitive only in some cases, OA is still a leading cause of euthanasia in dogs and a challenge for orthopedic surgeons. Recently, new therapeutic approaches, such as the use of autologous mesenchymal stem cells, have been developed. The purpose of this prospective, randomized, controlled, in vivo clinical study was to estimate the safety, feasibility, and efficacy of the intra-articular treatment of autologous microfragmented adipose tissue in dogs affected by spontaneous OA in comparison with a treatment with hyaluronic acid. Pain, lameness, the radiographic progression of OA, and synovial fluid inflammation were assessed. The results suggest that intra-articular injection of microfragmented autologous adipose tissue is safe, timesaving, cost-effective, minimally invasive, and can be easily done in one step. This treatment, compared with the hyaluronic acid treatment, showed better long-term pain control and an amelioration of synovial fluid quality, resulting in an improvement in joint function. This new treatment can be included among the effective therapies for OA. Additionally, the canine spontaneous OA model adopted in this study could play a key role in developing successful treatments for translational medicine.The purpose of this study was to estimate the safety, feasibility, and efficacy of the intra-articular treatment of autologous microfragmented adipose tissue in dogs with spontaneous osteoarthritis (OA) in comparison with hyaluronic acid (HA), the standard intra-articular treatment. Specifically, it clinically evaluated pain and lameness, the radiographic progression of osteoarthritis, and synovial fluid inflammation. This was a prospective, single-center, parallel-group, randomized, controlled, in vivo clinical study. Participants (n = 40) received either a single intra-articular injection of microfragmented adipose tissue or a single intra-articular injection of HA (1:1). Clinical outcomes were determined using a specialistic clinician assessment obtained by the completion of a specific clinical form based on the Vesseur modified lameness classification system, a pain evaluation using the Visual Analogue Scale (VAS), the measurement of the range of motion (ROM) of the affected joint, limb circumference, and the owners’ score evaluation using the Canine Brief Pain Inventory (CBPI) for up to 6 months after the time of injection. Patients underwent a radiographic examination to establish the degree of OA in the affected joint, and synovial fluid samples were collected to assess the biochemical environment of the joint and evaluate and quantify the cellular population and the presence of three specific inflammation biomarkers for up to 60 days. The results of this study suggest that microfragmented autologous adipose tissue is safe and can effectively relieve pain and improve function in dogs with spontaneous articular OA. This one-step procedure is simple, timesaving, cost-effective, minimally invasive, and eliminates the need for complex and time-intensive cell culture processing. Furthermore, the clinical evidence and cytological results suggest better long-term pain control, resulting in an improvement in joint function, compared to HA treatment. The canine spontaneous OA model could play a key role in developing successful treatments for human medicine.

USE OF MESENCHYMAL STEM CELLS IN THE TREATMENT OF BONE MARROW APLASIA IN DOGS

<h3>Background</h3> Bone marrow aplasia is a serious condition that affects dogs and cats. It is defined as a reduction or absence of all types of cells in the peripheral blood (pancytopenia) and hypoplasia of the three cell lines: erythroid, myeloid, and megakaryocyte in the bone marrow. The reduction or absence of one of these cell types is called hypoplasia, while the absence of the three cell types is called aplasia. Its causes can be infectious, hormonal, secondary to the use of drugs, toxins and radiation, neoplastic or idiopathic. The treatment of bone marrow aplasia in small animals is not well established, that way its objective is to stabilize the patient, who usually has profound anemia or significant thrombocytopenia, requiring transfusion of red blood cells or platelet concentrates, respectively. There is often no response to these therapies and alternatives are very few, making euthanasia an option. Thus, stem cell therapy has emerged as a new alternative for the treatment of bone marrow aplasia. Stem cells act by stimulating hematopoiesis, bringing important improvement to clinical signs and hematological exams, improving the patient‘s prognosis. The present clinical study aimed to demonstrate the beneficial effects of the application of multiple doses of allogeneic mesenchymal stem cells, derived from adipose tissue in dogs with bone marrow aplasia. <h3>Methods</h3> Eight dogs with bone marrow aplasia, confirmed by clinical and hematological exams, presenting persistent pancytopenia and refractory to treatment with antibiotics, corticosteroids and erythropoietin participated in the study. All animals had been receiving blood transfusions at variable intervals. The dogs received at least 3 intravenous applications of the solution containing mesenchymal stromal cells in intervals between 10 and 30 days. The doses administered contained at least 1 × 10⁷ viable MSCs. The interval between the first and the second application of MSCs varied between 10 and 15 days. <h3>Results</h3> All treated animals showed improvement in the hematological condition, with consequent spacing or interruption of blood transfusions, which resulted in a substantial improvement in quality and expectancy of life. <h3>Conclusion</h3> Serial application of 1 × 10⁷ MSCs proved to be a safe and good option of treatment, helping in the clinical improvement of dogs with bone marrow aplasia. These results present another therapeutic opportunity to be used in the treatment of this pathology.

Clinical signs of hypothyroidism in domestic dogs

The research was conducted during 2016–2019 on the basis of veterinary clinics in Poltava - veterinary clinic at the Department of Therapy named after Professor P.Lokes of Poltava State Agrarian Academy, “Vet Line”, “Vet Comfort” and the laboratory of the Department of Therapy named after Professor P. I. Lokes of Poltava State Agrarian Academy. During the research we studied 11 dogs, which were diagnosed with hypothyroidism. The animals belonged to different breeds, had different sexes (6 females and 5 males) and age. For control we took 15 dogs without visible signs of any pathology. We compared the breed susceptibility of dogs with hypothyroidism and dogs with alimentary obesity. Thus, we found that most breeds are common to animals in both pathologies. However, in our sample for hypothyroidism there was no such breed as a pug, and outbred individuals, which accounted for a significant percentage of dogs with alimentary obesity. One of the most common clinical symptom is the presence of symmetrical alopecia on the sides on the background of dull and disheveled hair (90.9 %). Mucosal anemia was observed in a significant proportion of animals (81.8 %). The symptom of bradycardia and shortness of breath during exercise is observed in 72.7 % of experimental animals, which indicates the development of pathological changes in the cardiovascular system. It was found that all animals showed depression, weakness and fatigue (100.0 %). Polydipsia and hypothermia were much less common in 45.5 % of dogs, and corneal dystrophy in 36.4% of cases. The last clinical manifestation occurred in animals with the most severe pathology. According to the literature, it is known that hypothyroidism in dogs is often a symptom of obesity. According to our data, obesity (overweight) was registered in 63.6 % of experimental animals. With the diagnosis of “hypothyroidism” in dogs, we identified two experimental groups: 1 – animals with normal fatness; 2nd – with a clinical symptom of obesity. We can note a significant increase in adipose tissue in dogs with hypothyroidism of the 2nd experimental group (45.1 ± 1.70 %), which indicates the presence of endocrine obesity, as evidenced by visual assessment of fatness (4.7 ± 0.18 points). Such changes develop due to insufficient production of thyroid hormones. The latter play an important role in regulating metabolism in the body. Due to their deficiency, the metabolism in animals slows down and, as a result, there is a risk of obesity.

PCB levels in adipose tissue of dogs from illegal dumping sites in Campania region (Italy).

The aim of the study is to investigate the potential relationship between exposure to PCBs and cancer. In doing so we relied on a sample of dogs coming from a peculiar area of the Campania region (Italy), that has been suffering for illegal waste dumping and open air burning of plastic waste for many years. The latter determined the release of organic and inorganic pollutants, such as the PCBs. By comparing dogs with cancer and healthy dogs, we found much higher PCB concentrations in the former, with a significant difference (p<0.05) for the non-indicator ∑10NDL-PCB and the DL-PCBs. A regression analysis, controlling for three potentially confounding factors, that are sex, age and weight, confirmed the higher ∑10NDL-PCB concentration in dogs with cancer. Hence, our evidence suggests a potential health hazard for animals and likewise people living in a risky area due to the presence of environmental organic pollutants.

ISOLAMENTO E CULTIVO DE CÉLULAS TRONCO MESENQUIMAIS EXTRAÍDAS DO TECIDO ADIPOSO E DA MEDULA ÓSSEA DE CÃES

Resumo Objetivou-se estabelecer um protocolo para extração, cultivo e expansão de células tronco mesenquimais (CTM), utilizando-se 3,0 mL da medula óssea e 3,0 cm3 de tecido adiposo do subcutâneo de três cães machos com seis meses de idade. As amostras foram processadas e as células extraídas e cultivadas em DMEM. Para comprovação do isolamento de CTM, procedeu-se a caracterização fenotípica e a diferenciação osteogênica, adipogênica e condrogênica. As células isoladas apresentaram morfologia alongada e fusiforme e capacidade de se diferenciar em osteoblastos, adipócitos e condrócitos. A caracterização fenotípica revelou alta expressão de marcadores de CTM CD90 (80,04%) e CD29 (96%) nas células de origem medular e CD90 (60,94%) e CD29 (77,08%) nas de origem adiposa. A expressão de marcadores hematopoiéticos foi baixa tanto nas células de origem medular CD45 (1,45%) e CD34 (1,53%), quanto nas de origem adiposa CD45 (1,45%) e CD34 (1,53%). As modificações e adaptações realizadas nos protocolos clássicos simplificaram o processo e foram eficientes, permitindo o isolamento e cultivo de CTM da medula óssea e do tecido adiposo de cães.

Subcutaneous and gonadal adipose tissue transcriptome differences in lean and obese female dogs

Canine obesity leads to shortened life span and increased disease incidence. Adipose tissue depots are known to have unique metabolic and gene expression profiles in rodents and humans, but few comparisons of depot gene expression have been performed in the dog. Using microarray technology, our objective was to identify differentially expressed genes and enriched functional pathways between subcutaneous and gonadal adipose of lean and obese dogs to better understand the pathogenesis of obesity in the dog. Because no depot × body weight status interactions were identified in the microarray data, depot differences were the primary focus. A total of 946 and 703 transcripts were differentially expressed (FDR P<0.05) between gonadal and subcutaneous adipose tissue in obese and lean dogs respectively. Of the adipose depot-specific differences in gene expression, 162 were present in both lean and obese dogs, with the majority (85%) expressed in the same direction. Both lean and obese dog gene lists had enrichment of the complement and coagulation cascade and systemic lupus erythematosus pathways. Obese dogs had enrichment of lysosome, extracellular matrix-receptor interaction, renin-angiotensin system and hematopoietic cell lineage pathways. Lean dogs had enrichment of glutathione metabolism and synthesis and degradation of ketone bodies. We have identified a core set of genes differentially expressed between subcutaneous and gonadal adipose tissue in dogs regardless of body weight. These genes contribute to depot-specific differences in immune function, extracellular matrix remodeling and lysosomal function and may contribute to the physiological differences noted between depots.

Quantification of achiral and chiral methylsulfonyl polychlorinated biphenyl metabolites by column-switching liquid chromatography–atmospheric pressure photoionization–tandem mass spectrometry

An enantioselective heart-cut column-switching liquid chromatography–atmospheric pressure photoionization–tandem mass spectrometry method was developed for the analysis of 25 methylsulfonyl polychlorinated biphenyl metabolites in tissue extracts. Use of a pyrenyl-ethyl silica column in the first dimension enabled separation of all but two pairs of isobaric analytes. Enantioseparation was achieved for 9 out of the 10 atropisomeric analytes using a Chiralpak AD-H amylose-based column within 93min, resulting in greater chromatographic resolution of enantioseparation over shorter analysis time by up to a factor of three, compared to previous one-dimensional and multi-dimensional gas chromatography-based methods. Precision for concentration and enantiomer fraction measurements was within 11% and 3% relative standard deviation, respectively. Limits of detection ranged from 0.01 to 1.73ng on-column. Meta-congeners had poorer sensitivity (i.e., ng on-column), consistent with existing gas chromatography-based methods. Despite this limitation, the method was successfully applied to the analysis of Greenland sledge dog adipose tissue extracts, which had highly non-racemic residues of 4-methylsulfonyl-2,2′,3,5′,6-pentachlorobiphenyl and 4′-methylsulfonyl-2,2′,3,3′,4,6′-hexachlorobiphenyl, consistent with past reports in Arctic mammals.

Production of canine mesenchymal stem cells from adipose tissue and their application in dogs with chronic osteoarthritis of the humeroradial joints

Autologous AD-MSC [adipose-derived MSC (mesenchymal stem cell)] therapy involves harvesting fat from the patient by isolating the stem and regenerative cells and administering the cells back to the patient. This study evaluated the production of canine AD-MSCs and their possible application in cellular therapy for dogs. To assess whether cellular therapy can replace drug therapy, the clinical effect of a single intra-articular injection of AD-MSCs was evaluated on 4 dogs with lameness associated with OA (osteoarthritis) of the humeroradial joints. MSCs were readily isolated from adult dog adipose tissue, and their ability to form colony and differentiate into various phenotypes was confirmed. AD-MSCs expressed OCT4, NANOG and SOX2 at the mRNA level, pluripotency markers usually ascribed to embryonic stem cells. The results suggest the stemness of the cells isolated from canine fat, and good quality control made them available for both experimental and clinical use. Follow-up studies to evaluate the effects of AD-MSC therapy showed that OA of the elbow joints improved with time, indicating significant potential for clinical use in the treatment of lameness, particularly when administered before the injury becomes severe.

Adipose tissue transcriptome changes during obesity development in female dogs

During the development of obesity, adipose tissue undergoes major expansion and remodeling, but the biological processes involved in this transition are not well understood. The objective of this study was to analyze global gene expression profiles of adipose tissue in dogs, fed a high-fat diet, during the transition from a lean to obese phenotype. Nine female beagles (4.09 ± 0.64 yr; 8.48 ± 0.35 kg) were randomized to ad libitum feeding or body weight maintenance. Subcutaneous adipose tissue biopsy, blood, and dual x-ray absorptiometry measurements were collected at 0, 4, 8, 12, and 24 wk of feeding. Serum was analyzed for glucose, insulin, fructosamine, triglycerides, free fatty acids, adiponectin, and leptin. Formalin-fixed adipose tissue was used for determination of adipocyte size. Adipose RNA samples were hybridized to Affymetrix Canine 2.0 microarrays. Statistical analysis, using repeated-measures ANOVA, showed ad libitum feeding increased (P < 0.05) body weight (0 wk, 8.36 ± 0.34 kg; 24 wk, 14.64 ± 0.34 kg), body fat mass (0 wk, 1.36 ± 0.24 kg; 24 wk, 6.52 ± 0.24 kg), adipocyte size (0 wk, 114.66 ± 17.38 μm(2); 24 wk, 320.97 ± 0.18.17 μm(2)), and leptin (0 wk, 0.8 ± 1.0 ng/ml; 24 wk, 12.9 ± 1.0 ng/ml). Microarrays displayed 1,665 differentially expressed genes in adipose tissue as weight increased. Alterations were seen in adipose tissue homeostatic processes including metabolism, oxidative stress, mitochondrial homeostasis, and extracellular matrix. Adipose transcriptome changes highlight the dynamic and adaptive response to ad libitum feeding and obesity development.

Comparison of adipose tissue changes following administration of rosiglitazone in the dog and rat

Rosiglitazone (BRL-49653-C), a thiazolidinedione, is a potent agonist for the nuclear hormone receptor peroxisome proliferator-activated receptor gamma (PPARgamma). Thiazolidinediones have been reported to induce adipocyte differentiation in vitro and there is limited data on their effects in vivo. The objective of this study was to compare the effects of rosiglitazone on adipocyte differentiation between dogs and rats. Morphological (light and ultrastructural) and morphometric evaluations were conducted on perirenal adipose tissue from dogs that have been treated for 1 month with 0.4, 5, 60 mg/kg/day and rats treated for the same period with 80 mg/kg/day. There was a dose-related change in the phenotype of white adipose tissue in dogs, reflected by an increase in nuclear numerical density (up to threefold) and cytoplasmic area fraction (up to 2.1-fold). In addition, there was an enlargement of the nuclei and a reduction in the size of the white adipocyte lipid vacuoles. Ultrastructural changes included an increase in the number of mitochondria per adipocyte. In the rat, similar changes were seen in nuclear numerical density (1.5-fold increase) and cytoplasmic area fraction (2.2-fold increase). There were also increased numbers of mitochondria per cell in white adipocytes giving them similar numbers of mitochondria to brown adipocytes. In the brown adipocytes, there was a reduction in cytoplasmic area fraction with a corresponding increase in the size of the lipid filled vacuoles in other words there was a converging of the phenotypes of the white and brown adipose tissues.

Anti-obesity effects of selective agonists to the beta 3-adrenergic receptor in dogs. I. The presence of canine beta 3-adrenergic receptor and in vivo lipomobilization by its agonists.

It is known that in rodents and humans the beta 3-adrenergic receptor (beta 3-AR) is present primarily in adipocytes and plays a significant role in the adrenergic stimulation of lipolysis. We examined the expression of beta 3-AR mRNA in the dog and the lipomobilizing effects of beta 3-AR-selective agonists in vivo. Reverse transcription polymerase chain reaction of RNA extracted from dog adipose tissue produced a cDNA fragment, the nucleotide sequence of which was highly homologous to the corresponding regions of human (86.4%) and mouse (79.5%) beta 3-AR cDNA. The beta 3-AR mRNA was present at high levels in subcutaneous and visceral adipose tissues, but undetectable in other organs. When a selective beta 3-AR agonist, CL316,243, was infused intravenously into beagle dogs, the plasma level of free fatty acid increased in 30 min and persisted at higher levels for several hours. ICI D7114, another beta 3-AR agonist, also showed a similar lipomobilizing effect, but with lower potency. beta 3-AR agonist infusion also increased the plasma insulin level. These results suggested that functional beta 3-AR is present in adipose tissues of the dog and that it is effective for in vivo lipomobilization.

Coexistence of beta 1-, beta 2-, and beta 3-adrenoceptors in dog fat cells and their differential activation by catecholamines

The existence of a beta 3-adrenoceptor (in addition to classical beta 1- and beta 2-), its involvement in the control of lipolysis and its recruitment by catecholamines were investigated in dog adipose tissue. Isoproterenol, norepinephrine, and the beta 2-selective agonist procaterol fully activated lipolysis in adipocytes (order of potency: isoproterenol > norepinephrine = procaterol). beta 3-Adrenergic agonists stimulated lipolysis with the order of potency: BRL 37344 > CGP 12177 > SR 58611A. Propranolol and bupranolol (nonselective beta-antagonists) antagonized, with a low potency, the effect of BRL 37344, whereas the beta 1-antagonist CGP 20712A and the beta 2-antagonist ICI 118551 were without action. CGP 20712A inhibited the effect of lower concentrations of agonists (0.05 microM isoproterenol, 0.1 microM norepinephrine and 0.1 microM procaterol) with an inhibitory constant (mean Ki) of 0.0075, 0.032 and > 10 microM, respectively. Mean Ki values for the beta 2-antagonist ICI 118551 were 1.744, 1.243, and 0.019 microM. This result indicates that low concentrations of isoproterenol and norepinephrine stimulate lipolysis mainly via beta 1-adrenoceptors in dog fat cells. Inversely, the lipolytic effect of higher concentrations of agonists i.e., 1 microM isoproterenol and catecholamines, was weakly antagonized by CGP 20712A or ICI 118551 while the nonselective beta-antagonists bupranolol and propranolol suppressed the effects with the order of potency expected for a beta 3-adrenoceptor: bupranolol > propranolol. These data indicate 1) the presence of a functional beta 3-adrenoceptor that coexists with beta 1- and beta 2-adrenoceptors in dog fat cells; 2) a separation of the differential potencies of physiological amines in the activation of lipolysis through beta 1-, beta 2-, and beta 3-adrenoceptors; the lipolytic response initiated at low concentrations (submicromolar range) of norepinephrine is primarily mediated by the beta 1-adrenoceptor subtype; and 3) an activation of the beta 3-adrenoceptor that occurs at higher concentrations of catecholamines.

Biochemical adaptations in the black-tailed prairie dog ( Cynomys ludovicianus) during long-term food and water deprivation

1. 1. Glucose and ketone body metabolism was studied in prairie dogs, which can withstand periods of food and water deprivation at near normal body temperatures without apparent utilization of body protein. 2. 2. Plasma glucose concentrations decreased by 18% (from 8.39 to 6.83 mM) when animals were deprived of food and water for 14 days during winter, and 27% (from 7.89 to 5.78 mM) after similar treatment in summer. 3. 3. Glucose utilization rates decreased by 33% (from 41.0 to 27.5 μmol/min/kg) during winter food and water deprivation, but changed little in summer animals (from 26.0 to 21.1 μmol/min/kg). 4. 4. Glucose carbon recycling was 30–31% in winter animals, but essentially zero in summer animals and did not change due to food and water deprivation. 5. 5. Analysis of the fatty acid composition of prairie dog adipose tissue showed no evidence of odd-number carbon fatty acids, a potential source of glucose carbon. No change in adrenal weights were noted. 6. 6. Ketone body concentrations increased 16-fold (from 0.039 to 0.641 mM) after food and water deprivation in the winter, while utilization rates increased 12-fold (from 0.42 to 4.88 μmol/min/100g). 7. 7. These results are discussed in relation to the ability of the prairie dog to adapt to long-term food and water deprivation.

Neuropeptide Y and peptide YY inhibit lipolysis in human and dog fat cells through a pertussis toxin-sensitive G protein.

Neuropeptide Y (NPY) and peptide YY (PYY) are regulatory peptides that have considerable sequence homology with pancreatic polypeptide. Because (a) NPY has been shown to be colocalized with noradrenaline in peripheral as well as central catecholaminergic neurons, and (b) alpha 2-adrenergic receptors of adipocytes play a major role in the regulation of lipolysis, we investigated the effect of NPY and PYY on isolated fat cells. In human fat cells NPY and PYY promoted a dose-dependent inhibition of lipolysis elicited by 2 micrograms/ml adenosine deaminase (removal of adenosine) whatever the lipolytic index used (glycerol or nonesterified fatty acids). In dog fat cells NPY and PYY inhibited adenosine deaminase-, isoproterenol- and forskolin-induced lipolysis. In humans and dogs the effects of NPY or PYY were abolished by treatment of cells with Bordetella pertussis toxin, clearly indicating the involvement of a Gi protein in the antilipolytic effects. This study indicates that, in addition to alpha 2-adrenergic agonists, NPY and PYY are also involved in the regulation of lipolysis in human and dog adipose tissue as powerful antilipolytic agents. Further studies are needed to characterize the pharmacological nature of the receptor mediating the inhibitory effect of NPY and PYY in fat cells.

Exercise-induced increase in dog adipose tissue blood flow before and after denervation.

Subcutaneous adipose tissue blood flow was examined during rest and exercise in the inguinal fat pads of four female dogs using the Xe wash-out technique. The experiments were performed before and after denervation of one of the pads. No difference between the resting flows in the two pads could be demonstrated either before or after denervation. The flow increased about two-fold on average from rest to exercise. This response was similar before and after denervation. It is concluded that direct sympathetic innervation is not involved in the regulation of adipose tissue blood flow during exercise.

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

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.

Component Patterns of Chlordanes in Human Milk, Cow's Milk, Dog Adipose Tissue, Cat Adipose Tissue and Wild Bird

The component patterns of chlordanes (total of 19 compounds) in human milk (n=12), cow's milk (n=10), dog adipose tissue (n=4), cat adipose tissue (n=6) and wild bird (2 species) were examined by mass spectrometry with selected ion monitoring. The component patterns in these samples were extremely different from those of aquatic biota described previously. In these higher animal samples, relatively high levels of residues of higher chlorine components (e. g. trans-, cis-nonachlor) and metabolites (oxychlordane, heptachlor epoxide) in relation to chlordanes were observed, though the component patterns varied in the different species of animal. High levels of residues of higher chlorine components were found in human milk, cat adipose tissue and wild bird samples, while the levels of metabolite residues were high in cow's milk and dog adipose tissue samples. The differences of component patterns may be due to species differences of metabolic activity.

Sympatho-adrenal regulation of adipose tissue blood flow in dog and man

1. 1. A comparison is made between the sympatho-adrenal regulation of subcutaneous adipose tissue blood flow in the dog and in man. 2. 2. In the dog neuronally released noradrenaline causes vasoconstriction in subcutaneous adipose tissue by preferential activation of α-adrenoceptors located close to the sympathetic nerve terminals. 3. 3. In man sympathetic reflex activation also causes vasoconstriction in subcutaneous adipose tissue, presumably via activation of α-adrenoceptors. 4. 4. The adipose tissue vascular β-adrenoceptors are of the β 1-subtype in the dog and the β 2-subtype in man. 5. 5. Because of this adrenaline causes vasoconstriction in dog adipose tissue and vasodilation in human adipose tissue.