Astrup A, Bülow J, Christensen N J
Acta Physiol Scand. 1985 May;124(1):81-5. doi: 10.1111/j.1748-1716.1985.tb07634.x.
In vitro experiments have demonstrated that increasing the molar ratio of extracellular non-esterified fatty acids (NEFA) to albumin stimulates thermogenesis in brown adipocytes. To test these results, in vivo blood flow and local temperature were measured in perirenal brown adipose tissue (BAT) in puppies during thermogenesis induced by increasing the plasma NEFA: albumin ratio by injection of intralipid and heparin. Plasma NEFA concentration increased to 1.5 mmol X 1-I and plasma NEFA:albumin ratio to 4. Concomitantly, the whole body oxygen consumption rose on average about 100% above baseline level. Plasma noradrenaline concentration increased about three-fold and plasma adrenaline concentration about six-fold. The BAT temperature increased by an average of 0.9 degrees C. However, since BAT blood flow was simultaneously reduced by about 50%, it can be calculated that the local heat production was also reduced. Consequently, the increase in whole body oxygen consumption was not due to stimulation of BAT thermogenesis. It is concluded that in vivo assessment of BAT thermogenesis requires concomitant measurements of both local BAT temperature and blood flow.
体外实验表明，增加细胞外非酯化脂肪酸（NEFA）与白蛋白的摩尔比可刺激棕色脂肪细胞的产热。为验证这些结果，通过注射脂肪乳剂和肝素提高血浆NEFA：白蛋白比值来诱导幼犬产热，在此过程中测量了幼犬肾周棕色脂肪组织（BAT）的体内血流量和局部温度。血浆NEFA浓度升至1.5 mmol·L⁻¹，血浆NEFA：白蛋白比值升至4。与此同时，全身耗氧量平均比基线水平升高约100%。血浆去甲肾上腺素浓度升高约三倍，血浆肾上腺素浓度升高约六倍。BAT温度平均升高0.9℃。然而，由于BAT血流量同时减少约50%，可以计算出局部产热也减少了。因此，全身耗氧量的增加并非由于BAT产热的刺激。结论是，对BAT产热进行体内评估需要同时测量局部BAT温度和血流量。
