Records |
Author |
McGreevy, P.D.; French, N.P.; Nicol, C.J. |
Title |
The prevalence of abnormal behaviours in dressage, eventing and endurance horses in relation to stabling |
Type |
Journal Article |
Year |
1995 |
Publication |
The Veterinary record |
Abbreviated Journal |
Vet. Rec. |
Volume |
137 |
Issue |
2 |
Pages |
36-37 |
Keywords |
Animal Husbandry/*methods; Animals; *Behavior, Animal; Horse Diseases/*psychology; Horses; *Physical Conditioning, Animal; Prevalence; Questionnaires; *Stereotyped Behavior |
Abstract |
The behaviour of horses competing in different disciplines was studied and the relationship between the time they spent out of the stable and the prevalence of abnormal behaviour was examined. The owners of dressage, eventing and endurance horses were sent a questionnaire and a total of 1101 responses were received, giving data on 1750 horses. The behaviours studied were wood-chewing, weaving, crib-biting/wind-sucking and box-walking. The reported percentage prevalences of abnormal behaviour for the dressage, eventing and endurance horses were 32.5, 30.8 and 19.5, respectively. The relationship between the time spent in the stable and the prevalence of abnormal behaviour was examined by chi 2 tests which showed that there were significant linear trends for the eventing group (P < 0.001) and the dressage group (P < 0.05). It is concluded that the time a horse spends out of the stable is related to the discipline for which it is being trained and in dressage and eventing horses the time spent in a stable is correlated with an increased risk of abnormal behaviour. |
Address |
University of Bristol, Department of Clinical Veterinary Science, Langford |
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
English |
Summary Language |
|
Original Title |
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0042-4900 |
ISBN |
|
Medium |
|
Area |
|
Expedition |
|
Conference |
|
Notes |
PMID:8525580 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
89 |
Permanent link to this record |
|
|
|
Author |
Nicol, C.J.; Brown, S.N.; Glen, E.; Pope, S.J.; Short, F.J.; Warriss, P.D.; Zimmerman, P.H.; Wilkins, L.J. |
Title |
Effects of stocking density, flock size and management on the welfare of laying hens in single-tier aviaries |
Type |
Journal Article |
Year |
2006 |
Publication |
British poultry science |
Abbreviated Journal |
Br Poult Sci |
Volume |
47 |
Issue |
2 |
Pages |
135-146 |
Keywords |
Animal Husbandry/*methods; *Animal Welfare; Animals; Body Constitution/*physiology; Chickens/*physiology; Crowding; Feathers; Female; *Housing, Animal/standards; Mortality; Organ Size; Oviposition/physiology; Population Density; Population Dynamics; Random Allocation |
Abstract |
Management practices, stocking rate and flock size may affect laying hen welfare but there have been few replicated studies in commercial non-cage systems that investigate this. This study used a broad range of physical and physiological indicators to assess the welfare of hens in 36 commercial flocks. Six laying period treatments were examined with each treatment replicated 6 times. It was not possible to randomly allocate treatments to houses, so treatment and house were largely confounded. Three stocking rates were compared: 7 birds/m(2) (n = 2450), 9 birds/m(2) (n = 3150) and 12 birds/m(2) in either small (n = 2450) or large (n = 4200) flocks. In addition, at 12 birds/m(2), in both small and large flocks, birds were subjected to either standard (SM) or modified (MM) management. MM flocks had nipple drinkers and no nest-box lights. Bone strength, fracture incidence, heterophil:lymphocyte (H:L) ratio, live weight, organ weights, serum creatine, serum osmolality, muscle pH and faecal corticosterone were measured on samples of birds at the end of the rearing period and at the end of lay. During the laying period, mortality, production and integument condition were recorded at regular intervals. Birds housed at 9 birds/m(2) had higher mortality than birds housed at 12 birds/m(2) by the end of lay, but not higher than birds housed at 7 birds/m(2). Birds housed at 7 and 9 birds/m(2) had lower percent liver weight, and worse plumage condition than most of the 12 bird/m(2) treatments. Modified management tended to improve plumage condition. There were no clear effects of flock size on the welfare indicators recorded. At the end of the rearing period fracture incidence was almost negligible and H:L ratio was within a normal range. By the end of lay fracture incidence was 60% and H:L ratio was high, with no treatment effect for either measure. This, together with information on faecal corticosterone, feather loss and mortality, suggests that the welfare of birds in all treatments was relatively poor by the end of lay. |
Address |
School of Veterinary Science, University of Bristol, Langford House, Langford BS40 5DU and ADAS Gleadthorpe, Meden Vale, Mansfield, Notts NG20 9PF, England. c.j.nicol@bristol.ac.uk |
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
English |
Summary Language |
|
Original Title |
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0007-1668 |
ISBN |
|
Medium |
|
Area |
|
Expedition |
|
Conference |
|
Notes |
PMID:16641024 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
65 |
Permanent link to this record |
|
|
|
Author |
McGreevy, P.D.; Nicol, C.J. |
Title |
The effect of short-term prevention on the subsequent rate of crib-biting in thoroughbred horses |
Type |
Journal Article |
Year |
1998 |
Publication |
Equine veterinary journal. Supplement |
Abbreviated Journal |
Equine Vet J Suppl |
Volume |
|
Issue |
27 |
Pages |
30-34 |
Keywords |
Analysis of Variance; Animals; *Behavior, Animal; Horse Diseases/*prevention & control/psychology; Horses; Male; Recurrence; *Stereotyped Behavior; Videotape Recording |
Abstract |
The results of an experimental study of the motivational consequences of short-term prevention of crib-biting are reported here. Eight test horses wore a cribbing collar for 24 h. This was effective in preventing crib-biting in 6 subjects. Using analysis of co-variance that accounted for baseline differences in crib-biting rate, test horses showed significantly more crib-biting than control horses on the first day after prevention (P < 0.05). There was also a highly significant increase in the crib-biting rate of test horses on the first day after prevention in comparison with their baseline rate (P < 0.01). This defines the increase as a post inhibitory rebound. An increase in the novelty of the cribbing bar and an increase in feeding motivation during the period of prevention are rejected as explanations of the rebound in this study. Instead, it is suggested that the rebound reflected a rise in internal motivation to crib-bite during the period of prevention. Behaviours that exhibit this pattern of motivation are generally considered functional; and it has been argued that their prevention may compromise welfare. |
Address |
Department of Clinical Veterinary Science, University of Bristol, UK |
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
English |
Summary Language |
|
Original Title |
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
|
ISBN |
|
Medium |
|
Area |
|
Expedition |
|
Conference |
|
Notes |
PMID:10485001 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
88 |
Permanent link to this record |
|
|
|
Author |
Ahrendt, L.P.; Labouriau, R.; Malmkvist, J.; Nicol, C.J.; Christensen, J.W. |
Title |
Development of a standard test to assess negative reinforcement learning in horses |
Type |
Journal Article |
Year |
2015 |
Publication |
Applied Animal Behaviour Science |
Abbreviated Journal |
Appl. Anim. Behav. Sci. |
Volume |
169 |
Issue |
|
Pages |
38-42 |
Keywords |
Algometry; Horse behaviour; Learning performance; Operant conditioning; Pressure-release; Horse training |
Abstract |
Most horses are trained by negative reinforcement. Currently, however, no standardised test for evaluating horses' negative reinforcement learning ability is available. The aim of this study was to develop an objective test to investigate negative reinforcement learning in horses. Twenty-four Icelandic horses (3 years old) were included in this study. The horses were tested in a pressure-release task on three separate days with 10, 7 and 5 trials on each side, respectively. Each trial consisted of pressure being applied on the hindquarter with an algometer. The force of the pressure was increased until the horse moved laterally away from the point of pressure. There was a significant decrease in required force over trials on the first test day (P<0.001), but not the second and third day. The intercepts on days 2 and 3 differed significantly from day 1 (P<0.001), but not each other. Significantly stronger force was required on the right side compared to the left (P<0.001), but there was no difference between first and second side tested (P=0.56). Individual performance was evaluated by median-force and the change in force over trials on the first test day. These two measures may explain different characteristics of negative reinforcement learning. In conclusion, this study presents a novel, standardised test for evaluating negative reinforcement learning ability in horses. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Summary Language |
|
Original Title |
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0168-1591 |
ISBN |
|
Medium |
|
Area |
|
Expedition |
|
Conference |
|
Notes |
|
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
6650 |
Permanent link to this record |
|
|
|
Author |
Cozzi, A.; Sighieri, C.; Gazzano, A.; Nicol, C.J.; Baragli, P. |
Title |
Post-conflict friendly reunion in a permanent group of horses (Equus caballus) |
Type |
Journal Article |
Year |
2010 |
Publication |
Behavioural Processes |
Abbreviated Journal |
Behav. Process. |
Volume |
85 |
Issue |
2 |
Pages |
185-190 |
Keywords |
aggression; affiliative interactions; conflict resolution; horse; post conflict; behaviour; reconciliation |
Abstract |
Gregarious animals living in permanent social groups experience intra-group competition. Conflicts over resources can escalate into costly aggression and, in some conditions, non-dispersive forms of conflict resolution may be favoured. Post-conflict friendly reunions, hence reconciliation, have been described in a variety of species. The aim of this study was to explore, for the first time, the occurrence of reconciliation in a group of domestic horses (Equus caballus) and learn more about strategies used to maintain group cohesion. The behaviour of seven horses living as permanent group in an enclosure for at least 2 years was observed by video for 108 h from June to August 2007. We used a Post-Conflict/Matched Control method to assess the existence of reconciliation and third-party affiliation. Behaviours recorded Post-Conflict, or during Matched Control periods, were classified as affiliative based on previous descriptions of visual communication patterns in horses. The proportion of attracted pairs over total post-conflict situations was significantly greater than the proportion of dispersed pairs, both during dyadic interactions (p < 0.001) and during triadic interactions (p = 0.002). The results of the present study show that both dyadic reconciliation and third-party post-conflict affiliative interactions form important social mechanisms for managing post-conflict situations in horses. |
Address |
|
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
|
Summary Language |
|
Original Title |
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0376-6357 |
ISBN |
|
Medium |
|
Area |
|
Expedition |
|
Conference |
|
Notes |
|
Approved |
no |
Call Number |
Equine Behaviour @ team @ |
Serial |
5168 |
Permanent link to this record |
|
|
|
Author |
Crosby, M.B.; Zhang, J.; Nowling, T.M.; Svenson, J.L.; Nicol, C.J.; Gonzalez, F.J.; Gilkeson, G.S. |
Title |
Inflammatory modulation of PPAR gamma expression and activity |
Type |
Journal Article |
Year |
2006 |
Publication |
Clinical immunology |
Abbreviated Journal |
Clin Immunol |
Volume |
118 |
Issue |
2-3 |
Pages |
276-283 |
Keywords |
Age Factors; Animals; Cell Line, Transformed; Cells, Cultured; Female; Inflammation Mediators/*physiology; Kidney/metabolism; Mesangial Cells/metabolism; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Inbred MRL lpr; Mice, Knockout; Nitric Oxide/biosynthesis; Nitric Oxide Synthase Type II/biosynthesis/genetics; PPAR gamma/*biosynthesis/*genetics/metabolism; Up-Regulation/immunology |
Abstract |
Nitric oxide (NO) production increases with age in the lupus-prone MRL/lpr mouse, paralleling disease activity. One mechanism for excess NO production in MRL/lpr mice may be a defect in down-regulatory mechanisms of the iNOS pathway. A potential modulator of NO is the nuclear hormone receptor peroxisome proliferation activated receptor gamma (PPARgamma). We demonstrate that renal PPARgamma protein expression was altered as disease progressed in MRL/lpr mice, which paralleled increased iNOS protein expression. Additionally, MRL/lpr-derived primary mesangial cells expressed less PPARgamma than BALB/c mesangial cells and produced more NO in response to LPS and IFNgamma. Furthermore, PPARgamma activity was reduced in mesangial cells following exposure to inflammatory mediators. This activity was restored with the addition of a NOS enzyme inhibitor. These results indicate that the activation of inflammatory pathways may lead to reduced activity and expression of PPARgamma, further exacerbating the disease state. |
Address |
Department of Medicine, Medical University of South Carolina, Charleston, SC 29425, USA |
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
English |
Summary Language |
|
Original Title |
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
1521-6616 |
ISBN |
|
Medium |
|
Area |
|
Expedition |
|
Conference |
|
Notes |
PMID:16303334 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
67 |
Permanent link to this record |
|
|
|
Author |
Waters, A.J.; Nicol, C.J.; French, N.P. |
Title |
Factors influencing the development of stereotypic and redirected behaviours in young horses: findings of a four year prospective epidemiological study |
Type |
Journal Article |
Year |
2002 |
Publication |
Equine veterinary journal |
Abbreviated Journal |
Equine Vet J |
Volume |
34 |
Issue |
6 |
Pages |
572-579 |
Keywords |
Age Factors; Animal Husbandry/*methods; Animal Welfare; Animals; *Behavior, Animal; Female; Horse Diseases/epidemiology/prevention & control/*psychology; Horses; Housing, Animal; Longitudinal Studies; Male; Prevalence; Prospective Studies; Risk Factors; *Stereotyped Behavior; Weaning |
Abstract |
Stereotypies are invariant and repetitive behaviour patterns that seemingly have no function, which tend to develop in captive animals faced with insoluble problems and may be indicative of reduced welfare. A 4 year prospective study of the factors influencing the development of stereotypic and redirected behaviours (abnormal behaviour) in a population of 225 young Thoroughbred and part-Thoroughbred horses was conducted between 1995 and 1999. Abnormal behaviour affected 34.7% of the population. Multivariable analysis showed that foals of low- or middle-ranking mares were less likely to develop abnormal behaviour than foals of dominant mares (rate ratio (RR) 0.23, P<0.01; RR 0.48, P<0.01, respectively). Weaning by confinement in a stable or barn was associated with an increased rate of development of abnormal behaviour, compared with paddock-weaning (RR 2.19, P<0.05), and housing in barns, rather than at grass after weaning, was associated with a further increase (RR 2.54, P<0.01). Specific stereotypic and redirected behaviours were then considered as separate outcomes. Crib-biting was initiated by 10.5% of horses at median age 20 weeks, weaving by 4.6% of horses at median age 60 weeks, box-walking by 2.3% of horses at median age 64 weeks and wood-chewing by 30.3% of horses at median age 30 weeks. Wood-chewing developed at a lower rate in horses born to subordinate or mid-ranking mares than in horses born to dominant mares (RR 0.29, P<0.01; RR 0.41, P<0.01, respectively), and at a higher rate in horses kept in barns or stables rather than at grass after weaning (RR 4.49, P<0.001; RR 1A6, P<0.001, respectively). Feeding concentrates after weaning was associated with a 4-fold increase in the rate of development of crib-biting (RR 4.12, P = 0.02). The results of this study support the idea that simple changes in feeding, housing and weaning practices could substantially lower the incidence of abnormal behaviour in young horses. |
Address |
University of Bristol, Department of Clinical Veterinary Science, Langford, Bristol, UK |
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
English |
Summary Language |
|
Original Title |
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0425-1644 |
ISBN |
|
Medium |
|
Area |
|
Expedition |
|
Conference |
|
Notes |
PMID:12357996 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
84 |
Permanent link to this record |
|
|
|
Author |
Albentosa, M.J.; Kjaer, J.B.; Nicol, C.J. |
Title |
Strain and age differences in behaviour, fear response and pecking tendency in laying hens |
Type |
Journal Article |
Year |
2003 |
Publication |
British poultry science |
Abbreviated Journal |
Br Poult Sci |
Volume |
44 |
Issue |
3 |
Pages |
333-344 |
Keywords |
Age Factors; Aggression/*physiology; Animal Husbandry; Animals; *Behavior, Animal; Breeding; Chickens/genetics/*physiology; Fear/*physiology; Feathers/*injuries; Female; Housing, Animal; Population Density; Social Behavior |
Abstract |
1. Behaviours associated with a high or low tendency to feather peck could be used as predictors of feather pecking behaviour in selective breeding programmes. This study investigated how strain and age at testing influenced responses in behavioural tests. 2. Four layer-type strains (ISA Brown, Columbian Blacktail, Ixworth and a high feather pecking (HP) and a low feather pecking (LP) line of White Leghorn) were reared in 6 same-strain/line pens of 8 birds from one day old. Birds in half the pens were given an open field test, a novel object test and a test with loose feather bundles between 4 and 12 weeks of age and a tonic immobility (TI) test at 13 weeks of age. All pens were tested with fixed feather bundles at 26 weeks, and undisturbed behaviour in the home pens was videoed at 1 and 27 weeks of age. Daily records of plumage damage were used as an indicator of feather pecking activity in the home pens. 3. Strain did not influence novel object test, open field test or loose feather test behaviour, although age effects in all three tests indicated a reduction in fearfulness and/or an increase in exploratory behaviour with increasing age. 4. White Leghorns showed longer TI durations than the other strains but less pecking at fixed feather bundles than ISA Browns and Columbian Blacktails. 5. There were few associations between behaviour in the 5 different tests, indicating that birds did not have overall behavioural traits that were consistent across different contexts. This suggests hens cannot easily be categorised into different behavioural 'types', based on their test responses and casts doubt on the usefulness of tests as predictors of feather pecking. |
Address |
Centre for Behavioural Biology, Division of Farm Animal Science, University of Bristol, Langford, Bristol, England. MAlbentosa@lincoln.ac.uk |
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
English |
Summary Language |
|
Original Title |
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0007-1668 |
ISBN |
|
Medium |
|
Area |
|
Expedition |
|
Conference |
|
Notes |
PMID:13677322 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
80 |
Permanent link to this record |
|
|
|
Author |
Nicol, C.J.; Adachi, M.; Akiyama, T.E.; Gonzalez, F.J. |
Title |
PPARgamma in endothelial cells influences high fat diet-induced hypertension |
Type |
Journal Article |
Year |
2005 |
Publication |
American journal of hypertension : journal of the American Society of Hypertension |
Abbreviated Journal |
Am J Hypertens |
Volume |
18 |
Issue |
4 Pt 1 |
Pages |
549-556 |
Keywords |
Administration, Oral; Animals; Antihypertensive Agents/pharmacology; Blood Pressure/drug effects; Diabetes Mellitus, Type 2/physiopathology; Dietary Fats/*administration & dosage/pharmacology; Dose-Response Relationship, Drug; Endothelial Cells/*metabolism; Female; Heart Rate/drug effects; Hypertension/*etiology; Ligands; Male; Mice; Mice, Knockout; PPAR gamma/*metabolism; Sodium Chloride/administration & dosage/pharmacology; Thiazolidinediones/pharmacology |
Abstract |
BACKGROUND: Peroxisome proliferator-activated receptor gamma (PPARgamma) ligands improve human hypertension. However, the mechanism and site of this effect remains unknown, confounded by PPARgamma expression in many cell types, including endothelial cells (ECs). METHODS: To evaluate the vascular role of PPARgamma we used a conditional null mouse model. Specific disruption of PPARgamma in ECs was created by crossing Tie2-Cre+ transgenic (T2T+) and PPARgamma-floxed (fl/fl) mice to generate PPARgamma (fl/fl)T2T+ (PPARgamma E-null) mice. Conscious 8- to 12-week-old congenic PPARgamma (fl/fl)Cre- (wild type) and PPARgamma E-null mice were examined for changes in systolic blood pressure (BP) and heart rate (HR), untreated, after 2 months of salt-loading (drinking water), and after treatment for 3 months with high fat (HF) diet alone or supplemented during the last 2 weeks with rosiglitazone (3 mg/kg/d). RESULTS: Untreated PPARgamma E-nulls were phenotypically indistinguishable from wild-type littermates. However, compared to similarly treated wild types, HF-treated PPARgamma E-nulls had significantly elevated systolic BP not seen after normal diet or salt-loading. Despite sex-dependent baseline differences, salt-loaded and HF-treated PPARgamma E-nulls of either sex had significantly elevated HR versus wild types. Interestingly, rosiglitazone improved serum insulin levels, but not HF diet-induced hypertension, in PPARgamma E-null mice. CONCLUSIONS: These results suggest that PPARgamma in ECs not only is an important regulator of hypertension and HR under stressed conditions mimicking those arising in type 2 diabetics, but also mediates the antihypertensive effects of rosiglitazone. These data add evidence supporting a beneficial role for PPARgamma-specific ligands in the treatment of hypertension, and suggest therapeutic strategies targeting ECs may prove useful. |
Address |
Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA |
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
English |
Summary Language |
|
Original Title |
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0895-7061 |
ISBN |
|
Medium |
|
Area |
|
Expedition |
|
Conference |
|
Notes |
PMID:15831367 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
69 |
Permanent link to this record |
|
|
|
Author |
Gavrilova, O.; Haluzik, M.; Matsusue, K.; Cutson, J.J.; Johnson, L.; Dietz, K.R.; Nicol, C.J.; Vinson, C.; Gonzalez, F.J.; Reitman, M.L. |
Title |
Liver peroxisome proliferator-activated receptor gamma contributes to hepatic steatosis, triglyceride clearance, and regulation of body fat mass |
Type |
Journal Article |
Year |
2003 |
Publication |
The Journal of biological chemistry |
Abbreviated Journal |
J Biol Chem |
Volume |
278 |
Issue |
36 |
Pages |
34268-34276 |
Keywords |
Adipose Tissue/*metabolism; Animals; Blotting, Southern; Blotting, Western; Female; Hypoglycemia/genetics; Insulin Resistance/genetics; Lipid Metabolism; Liver/*metabolism; Liver Diseases/genetics/*metabolism; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; RNA/metabolism; Receptors, Cytoplasmic and Nuclear/*genetics/*physiology; Recombination, Genetic; Thiazoles/pharmacology; *Thiazolidinediones; Time Factors; Transcription Factors/*genetics/*physiology; Triglycerides/*metabolism |
Abstract |
Peroxisome proliferator-activated receptor gamma (PPAR gamma) is a nuclear receptor that mediates the antidiabetic effects of thiazolidinediones. PPAR gamma is present in adipose tissue and becomes elevated in fatty livers, but the roles of specific tissues in thiazolidinedione actions are unclear. We studied the function of liver PPAR gamma in both lipoatrophic A-ZIP/F-1 (AZIP) and wild type mice. In AZIP mice, ablation of liver PPAR gamma reduced the hepatic steatosis but worsened the hyperlipidemia, triglyceride clearance, and muscle insulin resistance. Inactivation of AZIP liver PPAR gamma also abolished the hypoglycemic and hypolipidemic effects of rosiglitazone, demonstrating that, in the absence of adipose tissue, the liver is a primary and major site of thiazolidinedione action. In contrast, rosiglitazone remained effective in non-lipoatrophic mice lacking liver PPAR gamma, suggesting that adipose tissue is the major site of thiazolidinedione action in typical mice with adipose tissue. Interestingly, mice without liver PPAR gamma, but with adipose tissue, developed relative fat intolerance, increased adiposity, hyperlipidemia, and insulin resistance. Thus, liver PPAR gamma regulates triglyceride homeostasis, contributing to hepatic steatosis, but protecting other tissues from triglyceride accumulation and insulin resistance. |
Address |
Diabetes Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA. oksanag@bdg10.niddk.nih.gov |
Corporate Author |
|
Thesis |
|
Publisher |
|
Place of Publication |
|
Editor |
|
Language |
English |
Summary Language |
|
Original Title |
|
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
Series Volume |
|
Series Issue |
|
Edition |
|
ISSN |
0021-9258 |
ISBN |
|
Medium |
|
Area |
|
Expedition |
|
Conference |
|
Notes |
PMID:12805374 |
Approved |
no |
Call Number |
refbase @ user @ |
Serial |
81 |
Permanent link to this record |