Studies of on the biochemistry of insects. XIV. Metamorphosis hormones in insects

Abstract

Applyin the techniques of the extraction of metamorphosis hormones to an extract of Vespa vulgaris, active fractions have been obtained, which in determined dose produce a normal pig- mentation but do not produce the hardeness of the cuticle which is charasteristic in the pupation ; in other cases the pigmenta- tion is darker then usually, sometimes nearly black with me- lanines formation. Among these substances one has been iso- lated crystallized which experiences a modification at 150°, part of the molecule is decomposed at 205° C and fuses afterwards between 229° C and 238° C. The infra-red spectre in the same

indicates the presence of groupes NH or OH associated partially by bridges of H. If the proups are OH they are alcoho- lic. The groups COOH do not appear either as ester or amida or CO and there is probably a carboned chain with four or more atoms of carbón. They also seem to contain a double

connection very asimetric or, better several-conjugates.
The compound must be a cenapsa, which ineludes the ac­ tive substance, which in vitro is put on liberty by the heat

when the outer part is decomposing. In vivo, this liberation is realized by the enzimes, thus the activity is modified by time.