Arndt T, Nenoff P
Institute of Pathological Biochemistry, School of Medicine, University of Leipzig, Germany.
J Exp Anim Sci. 1992 Dec;35(3):136-43.
Differential temperature measurement between interscapular brown adipose tissue (BAT, Tbat), rectum (Trect) and a subcutaneous point in the back left of the vertebral column (Tsc) was useful for examination of BAT-thermogenesis in glutamate-induced obese Wistar-rats. Positive temperature gradients Tbat-Tsc pointed to a basal BAT-thermogenesis, whereas negative temperature gradients Tbat-Trect did not indicate that heat production in lean and obese rats. One may conclude from this, that inclusion of subcutaneous points outside the BAT improves sensitivity of differential temperature measurements for BAT-thermogenesis. Basal temperatures Tbat, Trect and Tsc were reduced in obese rats compared to lean rats, although thermoinsulation of obese rats is improved on account of their high fat content. This points to a diminished heat production in obese rats. Cold exposure at 4 degrees C elicited an increase of temperature gradients Tbat-Trect in lean as well as in obese rats, with positive values found only in lean rats. However, positive values Tbat-Tsc were calculated for both groups. Increases were noted only in lean rats. Injection of noradrenaline (0.5 mg/kg i.m.) was followed by positive temperature gradients Tbat-Trect and increased positive values for Tbat-Tsc, pointing to a remarkable activation of BAT-thermogenesis in lean and obese rats. These findings confirm, that glutamate-induced obese rats preserved the ability to activate BAT-thermogenesis. There were, however, hints of reduced heat production in BAT of obese rats, thus contributing to obesity despite normophagia.
测量肩胛间棕色脂肪组织（BAT，Tbat）、直肠（Trect）以及脊柱左侧背部皮下一点（Tsc）之间的温差，对于检测谷氨酸诱导肥胖的Wistar大鼠的BAT产热情况很有用。正的温度梯度Tbat - Tsc表明存在基础BAT产热，而负的温度梯度Tbat - Trect则未表明瘦鼠和肥胖鼠的产热情况。由此可以得出结论，纳入BAT以外的皮下测量点可提高BAT产热温差测量的灵敏度。与瘦鼠相比，肥胖鼠的基础温度Tbat、Trect和Tsc降低，尽管肥胖鼠因其高脂肪含量而改善了隔热能力。这表明肥胖鼠的产热减少。4℃的冷暴露使瘦鼠和肥胖鼠的温度梯度Tbat - Trect均升高，仅在瘦鼠中发现正值。然而，两组均计算出了正值Tbat - Tsc。仅在瘦鼠中观察到升高。注射去甲肾上腺素（0.5 mg/kg，肌肉注射）后，出现正的温度梯度Tbat - Trect，且Tbat - Tsc的正值增加，表明瘦鼠和肥胖鼠的BAT产热均有显著激活。这些发现证实，谷氨酸诱导肥胖的大鼠保留了激活BAT产热的能力。然而，有迹象表明肥胖鼠的BAT产热减少，因此尽管食量正常仍导致肥胖。
