Treatment with an ascochlorin derivative, AS-6 increases 45Ca2+ binding on the plasma membrane of adipocytes in db/db mice

Genetically obese diabetic mice (db/db) have greatly diminished 45Ca2+ binding on the plasma membranes of the adipocytes (45-55%) compared with their lean littermates. Treatment for 1 week with a diet admixture of AS-6 (0.1% in the diet) significantly restored the binding to a level comparable to the lean littermates. The addition of AS-6 in vitro had no effect on the binding, which eliminates the possibility that AS-6 is a Ca2+ ionophore. The results suggest that AS-6 treatment enhances the Ca2+ binding by causing structural alteration(s) in the membranes.