[Studies on the excitation-metabolism coupling mechanism in brown adipose tissues, 2; Effects of K+ and norepinephrine on the lipolysis in brown adipose tissues (author's transl)]

Abstract

This investigation was undertaken to clarify the lipolytic response caused by K+ and norepinephrine in brown adipose tissues. 1. Lipolytic response was obviously observed at the concentration of 50 mM in the K+-induced stimulation, and at 1.0 microgram/ml in the norepinephrine-induced stimulation, respectively. 2. K+- and norepinephrine-stimulated lipolysis were inhibited in the Ca2+-deficient tissues, and were inhibited by the addition of Mg2+, Mn2+ and La3+. 3. In the K+-stimulated lipolysis Ca2+ could be substituted only by Sr2+, while in the norepinephrine-stimulated lipolysis the substitution was possible with both Sr2+ and Ba2+. 4. K+- and norepinephrine-stimulated lipolysis were inhibited by the addition of propranolol and procaine. Accordingly, these positive results suggest that K+- and norepinephrine-stimulated lipolysis are dependent on the presence of Ca2+, and are related to the movements of Ca2+ and cyclic AMP system in the cells.