Naslov
Interscapular brown adipose tissue recruitment is hindered by a temperature environment of 33°C: uncoupling protein-1 underexpression is not associated with obesity development in rats

Autori
Jurić-Lekić, Gordana ; Bedrica, Ljiljana ; Lončar, Dragutin

Izvornik
Archives of Biological Sciences (0354-4664) 70 (2018), 3; 567-579

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
brown adipose tissue ; lipoprotein lipase, uncoupling protein ; heat stress ; mitochondria

Sažetak
Brown adipose tissue (BAT) generates heat due to unique thermogenic UC-mitochondria, an event known as nonshivering thermogenesis. Cold, adrenergic agents, hormones, etc., activate nonshivering thermogenesis, resulting in lipid mobilization, an increase in the mitochondria and mitochondrial cristae, and increase in the uncoupling protein-1 (UCP1) expression and its incorporation into mitochondrial cristae. BAT precursor cells mature and contribute to BAT growth. This entire process is known as BAT recruitment. For the first time, we herein report the effect of a thermoneutral environment of 33°C on the interscapular BAT (IBAT) in rats delivered and raised at 33°C. The control animals were housed at 20°C. Thermoneutral IBAT was atrophic (73 mg vs. 191 mg) but with more adipocyte precursor cells and euthermia (37.6°C) was maintained without nonshivering thermogenesis. Although IBAT was inactive, the thermoneutral animals did not develop obesity ; to the contrary, the thermoneutral environment of 33°C hindered the rats’ growth, weight (65 gm vs. 139 gm), volume (67 gm vs.136 gm) and length (12 cm vs. 16 cm). The thermoneutral brown adipocytes were smaller (7, 234 µm3 vs. 9, 198 µm3) with more lipids (4, 919 µm3 vs. 4, 507 µm3) and a smaller mitochondrial cristae area (52, 504 µm2 vs. 61, 288 µm2/adipocyte). Lipoprotein lipase mRNA expression was 11% (vs. 58% in control) and UCP1 mRNA expression was 34% (vs. 93% control). The UCP1 immunoelectron microscopic study detected 160 UCP1-gold particles (vs. 700 in control) per UC-mitochondrion, and thermoneutral brown adipocytes had 9-fold fewer UCP1-gold particles (0.34x106 vs. 2.99x106 UCP1-gold particles) and thermoneutral UC-mitochondria developed specific intramitochondrial tubular inclusions.

Izvorni jezik
Engleski

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