1
|
Xu X, Hu X, Ma G, Wang T, Wu J, Zhu X, Chen G, Zhao L, Chen J. Detecting fa leptin receptor mutation in Zucker rats with tetra-primer amplification-refractory mutation system (ARMS)-PCR. Heliyon 2023; 9:e20159. [PMID: 37809507 PMCID: PMC10559934 DOI: 10.1016/j.heliyon.2023.e20159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 09/05/2023] [Accepted: 09/13/2023] [Indexed: 10/10/2023] Open
Abstract
Due to the genetic mutation (fa) in the gene encoding for leptin receptor, homozygous Zucker rats (fa-/-) develop excessive adiposity and become an experimental animal model in obesity and metabolic-related diseases research. Based on tetra-primer amplification refractory mutation system-polymerase chain reaction (ARMS-PCR), we developed a method to quickly genotype Zucker rats with a mutated fa allele from their wildtype littermates. The three genotypes are clearly discriminated on 2.0% agarose gel. Our method can be used as a reliable tool to set up and maintain the breeding colony in animal facilities as well as assign animals to control and treatment groups based on their genotypes for animal studies.
Collapse
Affiliation(s)
- Xinyun Xu
- Department of Nutrition, The University of Tennessee Knoxville, TN, 37996, United States
| | - Xinge Hu
- Department of Nutrition, The University of Tennessee Knoxville, TN, 37996, United States
| | - Guodong Ma
- Department of Nutrition, The University of Tennessee Knoxville, TN, 37996, United States
| | - Tiannan Wang
- Department of Nutrition, The University of Tennessee Knoxville, TN, 37996, United States
| | - Jayne Wu
- Department of Electrical Engineering and Computer Science, The University of Tennessee Knoxville, TN, 37996, United States
| | - Xiaojuan Zhu
- Office of Information Technology, The University of Tennessee Knoxville, TN, 37996, United States
| | - Guoxun Chen
- Department of Nutrition, The University of Tennessee Knoxville, TN, 37996, United States
| | - Ling Zhao
- Department of Nutrition, The University of Tennessee Knoxville, TN, 37996, United States
| | - Jiangang Chen
- Department of Public Health, The University of Tennessee Knoxville, TN, 37996, United States
| |
Collapse
|
2
|
d'Amore A, Caiola S, Maroccia E, Loizzo A. Postnatal Stress in Mice: Effects on Body Fat, Plasma Lipids, Glucose and Insulin. Nutr Neurosci 2016; 3:207-14. [PMID: 27414054 DOI: 10.1080/1028415x.2000.11747317] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Mice pups were exposed to stressful stimuli everyday during the first 3 weeks of life. Body weight, food intake and spontaneous locomotor activity, triglycerides, cholesterol, phospholipids, glucose and insulin basal levels, as well as epididymal fat pad weight and its cell volume were measured in stressed and control animals. Results indicated that postnatal stressful manipulations induced an increase in body weight, epididymal fat pad weight and its cell volume, as well as in insulin, glucose, cholesterol and triglycerides plasma levels, at 4 months of age. No significant changes in food consumption, locomotor activity and phospholipids plasma levels were found. Present data suggest that early stressful manipulations may induce residual effects on lipid and glucid metabolism.
Collapse
Affiliation(s)
- A d'Amore
- a Laboratorio di Alimenti , Istituto Superiore di Sanità , Viale Regina Elena 299, 00161 Rome , Italy
| | - S Caiola
- b Laboratorio di Biochimica Clinica , Istituto Superiore di Sanità , Viale Regina Elena 299, 00161 Rome , Italy
| | - E Maroccia
- b Laboratorio di Biochimica Clinica , Istituto Superiore di Sanità , Viale Regina Elena 299, 00161 Rome , Italy
| | - A Loizzo
- c Laboratorio di Farmacologia , Istituto Superiore di Sanità , Viale Regina Elena 299, 00161 Rome , Italy
| |
Collapse
|
3
|
Beck B. Neuropeptide Y in normal eating and in genetic and dietary-induced obesity. Philos Trans R Soc Lond B Biol Sci 2007; 361:1159-85. [PMID: 16874931 PMCID: PMC1642692 DOI: 10.1098/rstb.2006.1855] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Neuropeptide Y (NPY) is one the most potent orexigenic peptides found in the brain. It stimulates food intake with a preferential effect on carbohydrate intake. It decreases latency to eat, increases motivation to eat and delays satiety by augmenting meal size. The effects on feeding are mediated through at least two receptors, the Y1 and Y5 receptors. The NPY system for feeding regulation is mostly located in the hypothalamus. It is formed of the arcuate nucleus (ARC), where the peptide is synthesized, and the paraventricular (PVN), dorsomedial (DMN) and ventromedial (VMN) nuclei and perifornical area where it is active. This activity is modulated by the hindbrain and limbic structures. It is dependent on energy availability, e.g. upregulation with food deprivation or restriction, and return to baseline with refeeding. It is also sensitive to diet composition with variable effects of carbohydrates and fats. Leptin signalling and glucose sensing which are directly linked to diet type are the most important factors involved in its regulation. Absence of leptin signalling in obesity models due to gene mutation either at the receptor level, as in the Zucker rat, the Koletsky rat or the db/db mouse, or at the peptide level, as in ob/ob mouse, is associated with increased mRNA abundance, peptide content and/or release in the ARC or PVN. Other genetic obesity models, such as the Otsuka-Long-Evans-Tokushima Fatty rat, the agouti mouse or the tubby mouse, are characterized by a diminution in NPY expression in the ARC nucleus and by a significant increase in the DMN. Further studies are necessary to determine the exact role of NPY in these latter models. Long-term exposure to high-fat or high-energy palatable diets leads to the development of adiposity and is associated with a decrease in hypothalamic NPY content or expression, consistent with the existence of a counter-regulatory mechanism to diminish energy intake and limit obesity development. On the other hand, an overactive NPY system (increased mRNA expression in the ARC associated with an upregulation of the receptors) is characteristic of rats or rodent strains sensitive to dietary-induced obesity. Finally, NPY appears to play an important role in body weight and feeding regulation, and while it does not constitute the only target for drug treatment of obesity, it may nevertheless provide a useful target in conjunction with others.
Collapse
Affiliation(s)
- B Beck
- Université Henri Poincaré, Neurocal, Nancy, France.
| |
Collapse
|
4
|
Mory G, Wiel M, Adli H, Diot-Dupuy F, Ferré P, Bazin R. Impaired beta-adrenergic signaling pathway in white adipocytes of suckling fa/fa Zucker rats: a defect in receptor coupling. Int J Obes (Lond) 2001; 25:1592-8. [PMID: 11753576 DOI: 10.1038/sj.ijo.0801811] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2000] [Revised: 02/22/2001] [Accepted: 05/08/2001] [Indexed: 11/08/2022]
Abstract
BACKGROUND In fa/fa Zucker rats, leptin receptor deficiency is responsible for both a deficit of energy expenditure and hyperphagia which lead to massive obesity and insulin resistance in adulthood. This obesity is also characterised by alterations of the beta-adrenergic signaling pathway. OBJECTIVE To determine whether alterations in beta-adrenergic pathway could occur at the onset of obesity when fa/fa rats are not yet hyperinsulinemic. ANIMALS Fourteen-day-old suckling fa/fa and Fa/fa littermates (from heterozygous lean (Fa/fa) female and homozygous obese (fa/fa) male mating). MEASUREMENTS Membranes were prepared from isolated adipocytes after collagenase treatment of inguinal adipose tissue. The response of adenylyl-cyclase activity to stimulation by isoprenaline, GTPgamma-S or forskolin was studied. Bmax and Kd of (beta1+beta2) and of beta3 adrenoceptors were measured using 3H-CGP saturation binding experiments. mRNA concentration of beta1- and beta3-AR was determined by semi-quantitative RT-PCR. G(s)alpha protein was quantified by Western blotting and Gi protein by ADP-ribosylation. RESULTS Despite an almost normal body weight, inguinal fat pad weight was increased two-fold by the expression of fa mutation. This increase was entirely accounted for by fat cell hypertrophy (x2.5 in volume). In fa/fa compared to Fa/fa pups, response of adenylyl cyclase to isoprenaline was decreased two-fold but responses to GTPgammaS or forskolin were unchanged. Density of (beta1+beta2) and beta3-AR was not affected by the fa/fa genotype, as well as G(s)alpha and Gi concentration. CONCLUSION Response of inguinal fat cells to catecholamines was decreased without any quantitative modifications of the different elements of the adenylyl cyclase cascade. This suggests an alteration in the coupling between beta-AR and G proteins. Due to the important increase in fat cell volume we hypothesize that changes in the physical properties of plasma membranes and/or changes in cytoskeleton-extracellular-matrix interactions could disturb the beta-adrenergic pathway responsiveness. In addition to the excess of lipid storage, which occurs very early at the onset of obesity, the impairment of the responsiveness to catecholamines reported in this study might worsen the obesity syndrome.
Collapse
MESH Headings
- Adenylyl Cyclases/drug effects
- Adenylyl Cyclases/metabolism
- Adipocytes/drug effects
- Adipocytes/metabolism
- Animals
- Animals, Newborn
- Blotting, Western
- Catecholamines/pharmacology
- Colforsin/pharmacology
- Female
- GTP-Binding Protein alpha Subunits, Gi-Go/metabolism
- GTP-Binding Protein alpha Subunits, Gs/metabolism
- Guanosine 5'-O-(3-Thiotriphosphate)/pharmacology
- Isoproterenol/pharmacology
- Male
- Obesity/genetics
- Obesity/metabolism
- RNA, Messenger/metabolism
- Rats
- Rats, Zucker
- Receptors, Adrenergic, beta/drug effects
- Receptors, Adrenergic, beta/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction/drug effects
Collapse
Affiliation(s)
- G Mory
- INSERM U 465, Centre Biomédical des Cordeliers, Paris, France
| | | | | | | | | | | |
Collapse
|
5
|
Truett GE, Walker JA, Harris RB. A developmental switch affecting growth of fatty rats. Am J Physiol Regul Integr Comp Physiol 2000; 279:R1956-63. [PMID: 11080058 DOI: 10.1152/ajpregu.2000.279.6.r1956] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fatty (fa/fa) rats accumulate more adipose mass than their littermates soon after birth, but they first appear obese during the fourth week of life. We analyzed the effects of fa genotype on growth of pups housed with their dams through 4 wk of age. The fa genotype effects on daily gain were undetectable from 7 to 22 days of age but became highly significant (P = 10(-18)) at 23 days of age. When litters were reduced to 4 pups, fa genotype effects on daily gain also became detectable at 23 days of age. The fa genotype effects on daily gain, stomach contents weight, liver weight, and plasma insulin of rats killed from 20 to 24 days of age displayed a marked genotype by age interaction, becoming highly significant at 23 days of age. These changes occur without the environmental changes induced by separating pups from their dams. These observations suggest that a developmental switch triggers hyperphagia and rapidly increases growth rate of fatty rats after 22 days of age.
Collapse
Affiliation(s)
- G E Truett
- Pennington Biomedical Research Center, Baton Rouge, Louisiana 70808, USA.
| | | | | |
Collapse
|
6
|
Abstract
This review focuses on the expression, content, and release of neuropeptides and on their role in the development of obesity in animal models with single-gene mutations. The balance between neuropeptides that contribute to the control of feeding behavior is profoundly and variously altered in these models, supporting the concept of the existence of several types of obesity. The hypothalamic neuropeptide Y (NPY) and the pro-opiomelanocortin (POMC) systems are the networks most studied in relation to energy intake. Both receive information about the nutritional status and the level of energy storage through insulin and leptin signaling mediated by specific receptors located on POMC and NPY neurons present predominantly in the arcuate nucleus (ARC). When leptin signaling is defective, through a defect in either the receptor (Zucker fa/fa rat, cp/cp rat, and db/db mouse) or in the peptide itself (ob/ob mouse), the NPY system is upregulated as shown by mRNA overexpression and increased peptide release, whereas the content and/or release of some inhibitory peptides (neurotensin, cholecystokinin) are diminished. For the POMC system, there is a complex interaction between the tonic inhibition of food intake exerted by alpha-melanocyte-stimulating hormone (alpha-MSH) and the Agouti-related protein at the level of the type 4 melanocortin receptor. The latter peptide is coexpressed with NPY in the ARC. Corticotropin-releasing factor (CRF) is the link between food intake and environmental factors. It not only inhibits food intake and prevents weight gain, likely through hypothalamic effects, but also activates the hypothalamo-pituitary axis and therefore contributes to energy storage in adipose tissue. The factors that prod the CRF system toward the hypothalamic or hypothalamo-pituitary axis system remain to be more clearly defined (comodulators, connections between limbic system and ARC, cellular location, and type of receptors, etc. ). The pathways used by all of these neuromodulators include numerous brain areas, but some interest has returned to the classic ones such as the ventromedial and lateral hypothalamic areas because of the recent discovery of some peptides (orexins and melanin-concentrating hormone for the lateral hypothalamus) and receptors (CRF type 2 in the ventromedial hypothalamus). All of these pathways are redundant and function in a coordinated manner and sometimes by the novel expression of a peptide in an unusual area. The importance of such a phenomenon in obesity remains to be determined. Even if single-gene mutations are exceptions in human obesity, the study of genetic animal models of obesity has greatly contributed to the understanding of the regulation of feeding behavior and will allow researchers to develop new drug treatments for obesity that have to be associated with drastic changes in lifestyle (feeding, work habits, and physical activity) for a complete efficiency.
Collapse
Affiliation(s)
- B Beck
- INSERM U.308 Mécanismes de Régulation du Comportement Alimentaire, Nancy, France.
| |
Collapse
|
7
|
d'Amore A, Loizzo A. Effects of neonatal treatment with Tyr-MIF-1 and naloxone on the long-term body weight gain induced by repeated postnatal stressful stimuli. Peptides 1999; 20:1425-30. [PMID: 10698117 DOI: 10.1016/s0196-9781(99)00152-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Stressful stimuli repeatedly applied during the first postnatal weeks can induce body weight gain in the mouse during adulthood. This effect can be prevented by injecting naloxone concomitantly with stress. The peptides belonging to the Tyr-MIF-1 family have a great modulating activity on numerous stress-induced phenomena. The aim of the present work was to compare the effect of repeated neonatal injections of Tyr-MIF-1 or naloxone on the long-term body weight gain induced by a stressing procedure applied daily during the first three weeks of life. The results indicate that although naloxone blocked the development of the stress-induced effects, Tyr-MIF-1 potentiated them.
Collapse
Affiliation(s)
- A d'Amore
- Laboratorio di Alimenti, Istituto Superiore di Sanità, Rome, Italy.
| | | |
Collapse
|
8
|
Coudray C, Charon C, Komas N, Mory G, Diot-Dupuy F, Manganiello V, Ferre P, Bazin R. Evidence for the presence of several phosphodiesterase isoforms in brown adipose tissue of Zucker rats: modulation of PDE2 by the fa gene expression. FEBS Lett 1999; 456:207-10. [PMID: 10452559 DOI: 10.1016/s0014-5793(99)00934-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The present study was undertaken to characterise the phosphodiesterases (PDEs) present in brown adipose tissue (BAT) of Zucker rat pups and to determine whether the capacity for degradation of cyclic nucleotides was affected by the fatty genotype. Regardless of the genotype, PDE2-4 contributed to total PDE activity, the PDE3 activity equalling the sum of PDE2 and 4 activities. In fa/fa compared to Fa/fa rats, (a) PDE2 activity was significantly increased, (b) Western blot analysis of PDE2 revealed two signals at 71 and 105 kDa, with changes in protein being in good parallelism with changes in activity, (c) the PDE2 mRNA concentration was also significantly increased. In good agreement, the cGMP concentration was decreased in BAT from fa/fa pups.
Collapse
|
9
|
Marques BG, Hausman DB, Martin RJ. Association of fat cell size and paracrine growth factors in development of hyperplastic obesity. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:R1898-908. [PMID: 9843879 DOI: 10.1152/ajpregu.1998.275.6.r1898] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Inguinal, epididymal, and retroperitoneal adipose tissue from lean and obese Zucker rats, 3-15 wk of age, was used to determine the association among adipocyte size distribution, the presence of paracrine growth factors in adipose tissue, and subsequent changes in adipocyte number. For each specific depot and time point, obese rats had a greater percentage of large adipocytes than did lean rats. A positive correlation (P < 0.02) was found in obese rats between the percentage of inguinal and epididymal adipocytes in the 140- to 180-micrometer size range and the ability of conditioned medium prepared from these depots to stimulate cellular proliferation in a bioassay system utilizing preadipocytes from inguinal fat pads of normal rats. Proliferative activity of the conditioned medium from all depots in obese rats was positively correlated (P < 0.01) to subsequent changes in fat cell number. The data presented here for the inguinal and epididymal depot of obese Zucker rats are consistent with the hypothesis that enlarged adipocytes secrete growth factors that induce preadipocyte proliferation.
Collapse
Affiliation(s)
- B G Marques
- Department of Foods and Nutrition, University of Georgia, Athens, Georgia 30602, USA
| | | | | |
Collapse
|
10
|
Amessou M, Fouque F, Soussi N, Desbuquois B, Hainaut I, Girard J, Benelli C. Longitudinal study of tissue- and subunit-specific obesity-induced regulation of the pyruvate dehydrogenase complex. Mol Cell Endocrinol 1998; 144:139-47. [PMID: 9863634 DOI: 10.1016/s0303-7207(98)00132-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The tissue-specific expression of the mitochondrial pyruvate dehydrogenase complex (PDHc) has been studied in an animal model of obesity with hyperinsulinemia, the obese (fa/fa) Zucker rat. Liver and heart were obtained from 4 and 8 week-old obese rats and age-matched lean animals, and in each tissue the following parameters were analyzed: (1) total activity of the mitochondrial PDHc; (2) abundance of the mitochondrial PDHc subunits on Western blots; and (3) abundance of the E1alpha and E1beta subunit mRNAs on Northern blots and semi-quantitative RT-PCR. Regardless of age, obese rats showed an increase in liver total PDHc activity and a coordinate increase in liver E1alpha and E1beta PDHc subunit abundance. At 4 weeks, obese rats also showed an increase in liver PDH E1alpha mRNA level, but regardless of age E1beta mRNA level was unchanged. In contrast, neither total PDHc activity nor the concentration of its protein subunits were increased in heart of obese rats. Thus, obese Zucker rats display a liver-specific early increase in PDHc which results from a selective up-regulation of the E1alpha gene expression.
Collapse
Affiliation(s)
- M Amessou
- INSERM U 30, Hôpital des Enfants Malades, Paris, France
| | | | | | | | | | | | | |
Collapse
|
11
|
Truett GE, Jacob HJ, Miller J, Drouin G, Bahary N, Smoller JW, Lander ES, Leibel RL. Genetic map of rat chromosome 5 including the fatty (fa) locus. Mamm Genome 1995; 6:25-30. [PMID: 7719022 DOI: 10.1007/bf00350889] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Thirteen loci, including the obesity gene fatty (fa), were incorporated into a linkage map of rat Chromosome (Chr) 5. These loci were mapped in obese (fa/fa) progeny of a cross between BN x 13M-fal+F1 animals. Obese rats were scored for BN and 13M alleles at four loci (Ifna, D1S85h, C8b, and Lck1) by restriction fragment length polymorphisms and at eight additional loci (Glut1, Sv4j2, R251, R735, R980, R252, R371, and R1138) by simple sequence length polymorphisms (SSLP). The resulting map spans 67.3 cM of Chr5, presenting nine previously unmapped loci and one locus (Lck1) previously assigned to Chr 5 by use of somatic cell hybrid lines. Seven of the eight SSLP loci are newly identified; the SSLP linkage group alone spans 56.8 cM. The order of the loci is Sv4j2-R251-R735-R980-R1138-Ifna-fa-+ ++D1S85h-C8b-(Glut1-R252-R371)-Lck1. One locus, D1S85h, was found to lie only 0.4 cM from fa, close enough to serve as a reliable marker for the prediction of phenotype from genotype, and will be useful also for studies on the development of obesity in the fatty rat.
Collapse
Affiliation(s)
- G E Truett
- Laboratory of Human Behavior and Metabolism, Rockefeller University, New York, New York 10021
| | | | | | | | | | | | | | | |
Collapse
|
12
|
Cleary MP, Phillips FC, Morton RA. Liver, serum and adipose tissue fatty acid composition in suckling Zucker rats. Lipids 1994; 29:753-8. [PMID: 7869855 DOI: 10.1007/bf02536696] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Young adult obese Zucker rats have altered tissue fatty acid (FA) composition. The present study was aimed at determining whether such changes were seen in either liver, serum or adipose tissue obtained from 17-day-old obese (fafa) rats in comparison to both homozygous (FaFa) and heterozygous (Fafa) lean rats. Body weights of obese pups (30.3 g) were significantly greater than those of homozygous lean rats (25.2 g) (P < 0.05). Liver weight and lipid content were similar in all groups. Inguinal fat pad weight and lipid content were greatest in obese pups (573 mg) followed by heterozygous lean pups (303 mg); homozygous lean pups (146 mg) had the lowest values. There were no differences among the groups in hepatic FA composition in either triacylglycerol (TG) or phospholipid fractions. Serum TG was similar among the groups, while serum phospholipid was greater (P < 0.05) in obese (269 mg/dL) than in homozygous lean pups (184 mg/dL); heterozygous lean pups had an intermediate value not significantly different from either homozygous group. On a percent basis, there were no differences in FA composition in either serum lipid fraction among the three groups. There were a number of significant differences in adipose tissue FA composition between the groups on a percent basis. The adipose tissue FA composition on a percent basis reflected that of maternal milk. The results indicate that suckling obese Zucker rats do not have tissue FA profiles that are characteristic of essential FA deficiency.
Collapse
Affiliation(s)
- M P Cleary
- Hormel Institute, University of Minnesota, Austin 55912
| | | | | |
Collapse
|
13
|
Cassis LA. Angiotensin II in brown adipose tissue from young and adult Zucker obese and lean rats. THE AMERICAN JOURNAL OF PHYSIOLOGY 1994; 266:E453-8. [PMID: 8166267 DOI: 10.1152/ajpendo.1994.266.3.e453] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Previous studies demonstrated that interscapular brown adipose tissue (ISBAT) produces angiotensin II (ANG II), which facilitates sympathetic neurotransmission (SN). ANG II content and regulation of SN were examined in young (17 days) and adult (16 wk) Zucker obese and lean rats. ANG II content in ISBAT from preobese rats was decreased compared with lean littermates. Evoked 3H overflow in ISBAT slices preloaded with [3H]NE was greater in preobese rats compared with control. ANG II increased evoked 3H overflow in ISBAT slices to a greater extent in preobese rats compared with control. [3H]NE uptake in ISBAT slices from preobese rats was decreased compared with control. In adult obese rats, plasma renin activity was decreased compared with control. ISBAT ANG II content was increased in adult obese rats compared with control. Evoked 3H overflow in ISBAT slices preloaded with [3H]NE was not different between obese and control. ANG II did not increase evoked 3H overflow in obese rats; however, ANG II increased evoked 3H overflow in lean rats. [3H]NE uptake in ISBAT slices from obese rats was decreased compared with control. These results suggest that ANG II modulation of SN activity is decreased in ISBAT from adult obese rats. In contrast, in young obese rats, increased SN activity and ANG II regulation of SN were evident in brown adipose tissue.
Collapse
Affiliation(s)
- L A Cassis
- Division of Pharmacology and Experimental Therapeutics, College of Pharmacy, University of Kentucky, Lexington 40536-0082
| |
Collapse
|
14
|
Guichard C, Dugail I, Le Liepvre X, Lavau M. Genetic regulation of fatty acid synthetase expression in adipose tissue: overtranscription of the gene in genetically obese rats. J Lipid Res 1992. [DOI: 10.1016/s0022-2275(20)41432-4] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
15
|
Beck B, Burlet A, Bazin R, Nicolas JP, Burlet C. Early modification of neuropeptide Y but not of neurotensin in the suprachiasmatic nucleus of the obese Zucker rat. Neurosci Lett 1992; 136:185-8. [PMID: 1641188 DOI: 10.1016/0304-3940(92)90045-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Hyperphagia in the obese Zucker rat is characterized by the early modification of the dark/light (D/L) rhythm of food intake. This rhythm is mainly driven by the suprachiasmatic nucleus (SCN) and, more controversially, by the ventromedian nucleus (VMN). In the SCN of adult obese Zucker rat, the concentrations of neuropeptide Y (NPY), a potent stimulator of food intake, are increased whereas those of neurotensin (NT), an anorexigenic peptide, are decreased. However, nothing is actually known about the synchronicity of the dysregulation of the D/L rhythm and variations of these peptides. That is why we measured NPY and NT in the microdissected SCN and VMN of lean (n = 16) and obese (n = 15) Zucker rats before the occurrence of hyperphagia (day 16 of age) and a few days after weaning (day 30 of age) when the modifications are apparent. For NPY, there was a very significant effect of age (P less than 0.001) for both nuclei and a significant effect of genotype (P less than 0.02) for the SCN only. NPY concentrations increased between 16 and 30 days in both nuclei (+74% (SCN) and +70% (VMN) in the obese rat; +57% (SCN) and +67% (VMN) in the lean rat; P less than 0.001). NPY in the SCN was not different at 16 days of age between lean and obese rats but significantly increased at 30 days in the obese rat (22.6 +/- 1.2 vs. 18.6 +/- 1.5 ng/mg protein; P less than 0.05). NT was not detected in the SCN of either group at 16 days or at 30 days.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- B Beck
- INSERM U. 308, Mécanismes de Régulation du Comportement Alimentaire, Nancy, France
| | | | | | | | | |
Collapse
|
16
|
Orosco M, Rouch C, Gripois D, Blouquit MF, Roffi J, Jacquot C, Cohen Y. Effects of insulin on brain monoamine metabolism in the Zucker rat: influence of genotype and age. Psychoneuroendocrinology 1991; 16:537-46. [PMID: 1725824 DOI: 10.1016/0306-4530(91)90037-t] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Disturbances of insulin or brain monoamine metabolism may play a role in the impaired regulation of food intake and body weight in the obese Zucker rat. We investigated a possible insulin-monoamine interaction by measuring monoamine levels in the hypothalamus and striatum of obese (fa-fa) and lean (Fa-Fa and Fa-fa) Zucker rats after peripheral insulin administration. The classically reported effects of insulin, i.e., increases in tryptophan, 5-hydroxy-indolacetic acid (5-HIAA) and dihydroxyphenylacetic acid (DOPAC) levels, were observed in the hypothalamus of Fa-Fa and Fa-fa rats, but not in obese fa-fa rats. Given the mechanism of action of insulin, this lack of effect in the obese rats may be related to the peripheral insulin resistance they exhibit. Furthermore, given the role of these monoaminergic systems, this reduced effect may be related to the impaired regulation of food intake and body weight. At 8 wk of age, however, insulin restored the decreased basal 5-HIAA levels observed in the obese rats. Increase in 5-HIAA levels following insulin administration appeared in the striatum of Fa-Fa rats only, suggesting that, as for brain insulin content, other central insulin-related disturbances may be related to the presence of the "fa" gene. In addition, certain effects of insulin on striatal dopamine release were observed in only the Fa-Fa and fa-fa rats, suggesting a particular disturbance related to the heterozygous character. This latter point calls for further investigations on the central dopaminergic effects of insulin.
Collapse
Affiliation(s)
- M Orosco
- Université Paris-Sud, URA-CNRS 594, Laboratoire de Pharmacologie, Faculté de Pharmacie, Châtenay-Malabry, France
| | | | | | | | | | | | | |
Collapse
|
17
|
Dugail I, Quignard-Boulangé A, Le Liepvre X, Lavau M. Impairment of adipsin expression is secondary to the onset of obesity in db/db mice. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(19)39902-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
18
|
Escoubet B, Griffaton G, Guesnet P, Lechat P, Lavau M. Prostaglandin synthesis and membrane fatty acid composition in the heart of obese Zucker rats. Biochem Biophys Res Commun 1987; 146:589-95. [PMID: 3113424 DOI: 10.1016/0006-291x(87)90569-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Genetically obese Zucker rats share several abnormalities with obese patients: inheritance of the obesity, hyperinsulinemia, hypertriglyceridemia. Because alterations in membrane fatty acid composition and in prostaglandin synthesis can be involved in the genesis of the cardiovascular complications of obesity, cardiac prostaglandins and phospholipid fatty acid composition were compared in obese and lean animals. Obese cardiac tissues produced smaller amounts of prostacyclin, thromboxane A2 and PGE2 than lean (p less than 0.01). The cyclooxygenase pathway and the activation of phospholipase by the calcium ionophore A 23187 were not altered. Phospholipid fatty acid composition of obese tissues was abnormal: the amount of stearic, arachidonic, docosapentaenoic and cervonic acids was decreased, whereas the amount of linoleic acid, the precursor of arachidonic acid, was doubled. It is concluded that obesity in Zucker rats is associated with alteration of cardiac arachidonic acid metabolism and that the alterations associated with obesity can be studied in this rat strain.
Collapse
|
19
|
York D, Holt S, Rothwell N, Stock M. Effect of age and gene dosage on brown adipose tissue of Zucker obese fa/fa rats. THE AMERICAN JOURNAL OF PHYSIOLOGY 1984; 246:E391-6. [PMID: 6720944 DOI: 10.1152/ajpendo.1984.246.5.e391] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Experiments were performed to investigate the effect of age and genotype on brown adipose tissue thermogenesis in Zucker rats. Specific [3H]GDP binding to interscapular brown adipose tissue mitochondria ( IBATM ) was reduced in 14-day-old preobese fa/fa rats and remained lower after weaning. A gene-dosage effect of the recessive fa gene was observed in 8- to 10-wk-old rats in both IBATM [3H]GDP binding and the thermic effect of a balanced meal (50 kJ Complan ), measured by indirect calorimetry. In each case the heterozygote (Fa/fa) group had a value intermediate between those of obese (fa/fa) and the homozygous lean (Fa/Fa) groups. Norepinephrine increased IBATM [3H]GDP binding to similar levels in lean (Fa/fa) and obese (fa/fa) rats and induced similar increases in oxygen consumption in Fa/Fa, Fa/fa, and fa/fa rats. It is concluded that the impaired, diet-related brown adipose tissue thermogenesis is closely related to the primary gene defect in the obese rat. This defect may result from misregulation of the autonomic nervous system.
Collapse
|
20
|
Bazin R, Lavau M. Development of hepatic and adipose tissue lipogenic enzymes and insulinemia during suckling and weaning on to a high-fat diet in Zucker rats. J Lipid Res 1982. [DOI: 10.1016/s0022-2275(20)38086-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|