Feyereisen R, Lagueux M, Hoffmann J A
C R Acad Hebd Seances Acad Sci D. 1975 Apr 14;280(14):1709-12.
Shortly after injection of radio-labelled ecdysone into fifth instar larvae of Locusta migratoria, 20-hydroxy-ecdysone (ecdysterone) is the main hormone found in the blood. Some 10% of the circulating hormone are bound to hemolymph macromolecules. The ratio of bound to free hormone is stage-dependent; it decreases considerably after previous injections of non-labelled ecdysone, but increases in insects in which ecdysone biosynthesis has been blocked by extirpation of the prothoracic glands or selective X-ray treatment of the hemocytopoietic tissue.