The inhibition of protein synthesis in Locusta migratoria by adipokinetic hormone

Injection of glandular lobe extracts or synthetic adipokinetic hormone caused a suppression of haemolymph protein synthesis in adults in a dose-dependent manner. The inhibition of protein synthesis occurred at lower doses of adipokinetic hormone than that necessary to cause mobilization of lipid. The effect lasted approximately the same time as the elevation of haemolymph lipid. At higher doses, the hormone was less effective in inhibiting protein synthesis, though lipid mobilization did not change. Incubation of isolated half fat bodies in vitro in the presence or absence of either glandular lobes or adipokinetic hormone confirmed the in vivo results. Protein synthesis in heart and midgut tissue was also inhibited by adipokinetic hormone. Both arylphorin and vitellogenin synthesis were inhibited upon injection of the hormone into vitellogenic female locusts.