Lipase Activity in the Slow- and Fast-contracting Leg Muscles of the Cockroach

THE recent work of Becht and Dresdon1 and Smit2 has brought to light certain histological and physiological features of the slow- and fast-contracting mesothoracic leg muscles of the cockroach, Periplaneta americana. Smit2 has shown that the slow-contracting muscle fibres contain more lipids and possess a stronger reducing capacity for methylene blue than the fast-contracting ones. Histochemical investigation of these two types of fibres3 has shown that there is more lipase activity in the slow-contracting muscles. Here we report the results of a quantitative investigation of lipase activity in the slow- and fast-contracting leg muscles of the cockroach.