Potassium‐induced increase in oxygen consumption of brown adipose tissue from the rat.

Abstract

SUMMARY1. In brown adipose tissue, noradrenaline induces an increase in respiration and a depolarization of the cells. The effect of an increase in potassium concentration in a range known to depolarize the brown adipocytes was tested on the 02 consumption.2. Isolated interscapular brown adipose tissue from the rat was incubated in chambers that allowed 02 consumption to be measured over prolonged periods.3. 45-50 mM-KCl were found to induce a more than fourfold increase in 02 consumption, which was stable, reversible and dependent upon the presence of calcium in the medium. 4. When rats were pre-treated with reserpine or 6-hydroxydopamine the KCl-induced increase in 02 consumption was sharply reduced or entirely absent.5. The effect of KCI was greatly inhibited by (-)-propranolol, but not by (+ )-propranolol.6. Moderate increases in 02 consumption induced by low concentrations of potassium were potentiated by desipramine, a drug which is known to block the uptake of catecholamines by adrenergic nerve endings.7. Surgical denervation caused a decrease in the catecholamine content of the tissue, but had no effect on the KCl response.8. It is concluded that in brown adipose tissue, potassium stimulates 02 consumption by causing a release of noradrenaline from nerve endings. This implies that surgical denervation as it is commonly performed on this tissue does not denervate the brown adipocytes but probably only the blood vessels.

Microcalorimetric determination of energy expenditure due to active sodium‐potassium transport in the soleus muscle and brown adipose tissue of the rat.

“…Control experiments performed without tissue in the calorimeter showed no detectable change in the base-line following the transition from normal medium to one containing 1O-3M ouabain. (Barde et al 1975). In brown adipose tissue isolated from reserpine treated rats (6 mg .…”

“…The basal rate of heat production was compared with the basal rate of 0, consumption in two ways: in one series of the experiments, the 02-uptake in the contralateral muscle was measured using an 02 cathode in a bubble-free liquid phase (Barde, Chinet & Girardier, 1975). In another series, direct comparison of heat production and 02-uptake was achieved by measuring Po.…”

The direct effect of leptin on skeletal muscle thermogenesis is mediated by substrate cycling between de novo lipogenesis and lipid oxidation

“…The respiratory rate ( M O 2 ) of skeletal muscle was measured by a method involving repeated O 2 uptake determinations, as described by Barde et al [10]. The O 2 partial pressure of a bubble‐free liquid phase enclosed in a thick‐walled Lucite chamber was measured by a Clark O 2 electrode connected to a polarographic circuit, whose output voltage is directly proportional to the O 2 partial pressure.…”

Thyroid hormones and the energetics of active sodium‐potassium transport in mammalian skeletal muscles.

“…The direct microcalorimetric method allowing quantitative determination of small changes in the rate of heat production, provided they are acutely induced during a steady state, has been described in detail previously (Chinet et al 1977). Indirect calorimetry in a stop-flow respirometer (Barde, Chinet & Girardier, 1975) was used in a few control experiments. Since it is very difficult, if not impossible, to measure the metabolic rate of an intact diaphragm muscle, calorimetric measurements were done on soleus muscles only.…”