The effect of myo-inositol deficiency on lipid metabolism in rats. III. The mechanism of an enhancement in lipolysis due to myo-inositol deficiency in rats.

myo-Inositol deficiency in rats produced an overaccumulation of triacylglycerols in the liver due to stimulated lipolysis in the adipose tissue (Hayashi, E., Maeda, T. and Tomita, T. (1974) Biochim. Biophys. Acta 360, 134--155). The mechanism of the enhancement in lipolysis has now been investigated. The lipolytic response to adrenalin, corticotropin and insulin of the epididymal adipose tissue did not change due to the deficiency, but hormone-sensitive lipase activity, plasma adrenalin level and blood pressure were higher in the deficient rats. Adrenalectomy had no influence, but administration of sympathetic nervous blockers (reserpine, hexamethonium and bupranolol) inhibited the liver lipid deposition and an increase of serum free fatty acids in the deficient rats. These results indicate that the enhancement in lipolysis is mediated by an excitation of sympathetic nerve terminals innervating in the adipose tissues.