Autocrine effects of transgenic resistin reduce palmitate and glucose oxidation in brown adipose tissue.
Resistin has been originally identified as an adipokine that links obesity to insulin resistance in mice. In our previous studies in spontaneously hypertensive rats (SHR) expressing a nonsecreted form of mouse resistin (Retn) transgene specifically in adipose tissue (SHR-Retn), we have observed an increased lipolysis and serum free fatty acids, ectopic fat accumulation in muscles, and insulin resistance. Recently, brown adipose tissue (BAT) has been suggested to play an important role in the pathogenesis of metabolic disturbances. In the current study, we have analyzed autocrine effects of transgenic resistin on BAT glucose and lipid metabolism and mitochondrial function in the SHR-Retn vs. nontransgenic SHR controls. We observed that interscapular BAT isolated from SHR-Retn transgenic rats compared with SHR controls showed a lower relative weight (0.71 ± 0.05 vs. 0.91 ± 0.08 g/100 g body wt, P < 0.05), significantly reduced both basal and insulin stimulated incorporation of palmitate into BAT lipids (658 ± 50 vs. 856 ± 45 and 864 ± 47 vs. 1,086 ± 35 nmol/g/2 h, P ≤ 0.01, respectively), and significantly decreased palmitate oxidation (37.6 ± 4.5 vs. 57 ± 4.1 nmol/g/2 h, P = 0.007) and glucose oxidation (277 ± 34 vs. 458 ± 38 nmol/g/2 h, P = 0.001). In addition, in vivo microPET imaging revealed significantly reduced (18)F-FDG uptake in BAT induced by exposure to cold in SHR-Retn vs. control SHR (232 ± 19 vs. 334 ± 22 kBq/ml, P < 0.05). Gene expression profiles in BAT identified differentially expressed genes involved in skeletal muscle and connective tissue development, inflammation and MAPK and insulin signaling. These results provide evidence that autocrine effects of resistin attenuate differentiation and activity of BAT and thus may play a role in the pathogenesis of insulin resistance in the rat.
Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic; pravenec@biomed.cas.cz.
Michal
M
Pravenec
Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic;
Petr
P
Mlejnek
Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic;
Václav
V
Zídek
Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic;
Vladimír
V
Landa
Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic;
Miroslava
M
Šimáková
Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic;
Jan
J
Šilhavý
Institute of Molecular Genetics, Czech Academy of Sciences, Prague, Czech Republic;
Hynek
H
Strnad
Nuclear Physics Institute, Czech Academy of Sciences, Husinec-Řež, Czech Republic, Faculty of Pharmacy, Charles University in Prague, Hradec Králové, Czech Republic;
Sebastian
S
Eigner
Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic;
Kateřina
K
Eigner Henke
Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
Vojtěch
V
Škop
Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
Hana
H
Malínská
Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
Jaroslava
J
Trnovská
Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
Ludmila
L
Kazdová
Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic;
Zdeněk
Z
Drahota
Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic;
Tomáš
T
Mráček
Institute of Physiology, Czech Academy of Sciences, Prague, Czech Republic;
Josef
J
Houštěk
D002001:Adipose Tissue, Brown / Q000378:metabolism* / Q000502:physiology; D000818:Animals; D019898:Autocrine Communication / Q000235:genetics / Q000502:physiology*; D005230:Fatty Acids, Nonesterified / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D007328:Insulin / Q000378:metabolism; D007333:Insulin Resistance / Q000502:physiology; D050356:Lipid Metabolism / Q000502:physiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008928:Mitochondria / Q000235:genetics / Q000502:physiology; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology; D009765:Obesity / Q000378:metabolism / Q000503:physiopathology; D010084:Oxidation-Reduction; D010168:Palmitates / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D055647:Rats, Transgenic; D052243:Resistin / Q000235:genetics*; D059467:Transcriptome / Q000235:genetics
D005230:Fatty Acids, Nonesterified; D007328:Insulin; D010168:Palmitates; D052243:Resistin; D005947:Glucose
autocrine; brown adipose tissue; resistin; spontaneously hypertensive rat; transgenic