FATTY-ACID-BINDING PROTEIN EXPRESSION IN LOCUST FLIGHT-MUSCLE - INDUCTION BY FLIGHT, ADIPOKINETIC HORMONE, AND LOW-DENSITY LIPOPHORIN

Fatty acid binding protein (FABP) is a major cytosolic protein in the flight muscle of the adult desert locust, Schistocerca gregaria. While it is normally expressed at high rates only at the beginning of the a dult stage, a marked increase in FABP mRNA accumulation can be induced by flight. Extended flight leads to a 10-fold increase of FABP mRNA w ithin 12 h. Injection of adipokinetic hormone which mobilizes lipid de livery also stimulates FABP transcription in a dose-dependent manner. FABP mRNA reaches its maximum 16 h after treatment and returns to its base level within 48 h. Purified low density lipophorin, when injected into resting locusts, causes a similar increase as adipokinetic hormo ne or flight, suggesting that the additional supply of fatty acids is the ultimate cause for the observed induction of FABP expression.