[Effects of K+ or norepinephrine on oxygen uptake in brown adipose tissue (author's transl)].
This investigation was undertaken to clarify the mechanism of the stimulated--respiration caused by K+ or norepinephrine in brown adipose tissue. 1. The addition of 30 approximately 100 mM K+ stimulated remarkably oxygen uptake in brown adipose tissue, and similarly norepinephrine (0.1 or 1.0 mug/ml) caused a marked stimulation. 2. Even if Na+ in normal Ringer solution was replaced by Choline or Li+, oxygen uptake caused by K+ (30 mM) or norepinephrine (1.0 mug/ml) was unaffected. 3. K+ -induced oxygen uptake was not observed when a Ca2+ -deficient tissue was incubated in Ca2+ -free Ringer, while norepinephrine-induced oxygen uptake clearly observed. And the oxygen uptake of Ca2+ -deficient tissue due to K+ was recovered by the addition of 5 mM Ca2+. 4. Mn2+ (6 mM) or La3+ (10 mM) inhibited significantly oxygen uptake due to K+, but not oxygen uptake due to norepinephrine. 5. K+ -induced oxygen uptake was unaffected by 10(-4) or 10(-3)M ouabain, but norepinephrine-induced oxygen uptake was inhibited considerably by 10(-4)M ouabain. 6. The oxygen uptake due to K+ was unaffected by propranolol (33 muM), whereas that due to norepinephrine was significantly inhibited in the presence of propranolol. 7. In the tissue from reserpine-treated animal, the oxygen uptake caused by K+ was observed. According, from these positive results we are justified to suggest that K+ -induced oxygen uptake is dependent on the presence of Ca2+, and not always caused by catecholamines released secondarily from nerve terminal.
D002001:Adipose Tissue, Brown / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000494:pharmacology; D066298:In Vitro Techniques; D007811:Lanthanum / Q000494:pharmacology; D008094:Lithium / Q000494:pharmacology; D008297:Male; D008345:Manganese / Q000494:pharmacology; D009638:Norepinephrine / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D010042:Ouabain / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects*; D011188:Potassium / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D012110:Reserpine / Q000494:pharmacology
D008345:Manganese; D010042:Ouabain; D007811:Lanthanum; D012110:Reserpine; D008094:Lithium; D011433:Propranolol; D011188:Potassium; D002118:Calcium; D009638:Norepinephrine