Lithium increases turnover of phospholipids in flight muscles of Periplaneta americana L.

The effect of prolonged lithium administration on the phospholipid metabolism of flight muscles of the cockroach Periplaneta americana has been studied. Following daily injections of LiCl in a dose of 19.25 mumol LiCl per gram of wet weight [32P]- orthophosphate were injected and its incorporation into the phospholipids was measured 2, 12 and 24 h later. Lithium administration did not change the content of phospholipids but increased the 32P incorporation into phosphatidylinositol, phosphatidylcholine, phosphatidylethanolamine and sphingomyeline 1.87, 2.13, 2.02 and 1.87 times, respectively, as compared with the control values. These increases were neither due to an increased permeability of the tissue for inorganic phosphate nor to an increased turnover of gamma-P-ATP. It is concluded that prolonged lithium treatment increases the turnover of all phospholipids in insect flight muscle tissue.