2 NEW ALLATOSTATINS FROM THE BRAINS OF DIPLOPTERA-PUNCTATA

Allatostatins VI and VII have been isolated from saline e?rtracts of t he brain of the viviparous cockroach Diploptera punctata. Active fract ions, obtained by successive reverse-phase high pressure liquid chroma tography separations, inhibited juvenile hormone (JH) III production b y corpora allata (CA) in vitro. The primary structures, Y-P-Q-E-H-R-F- S-F-G-L-amide (VI) and D-G-R-M-Y-S-F-G-L-amide (VII), clearly identify them as members of a family of D. punctata allatostatins, five of whi ch have been identified previously and shown to have F-G-L-amide at th e C terminus. Synthetic allatostatins VI and VII coeluted with the nat ive allatostatins on two successive high pressure liquid chromatograph y separations. Allatostatins VI and VII have the same capacity to inhi bit JH production by CA of 2 day virgin females as does allatostatin I , previously shown to be a potent inhibitor similar in activity to all atostatin V. Allatostatins VI and VII also resemble the other allatost atins in their ability to affect both larval and adult CA, in the reve rsibility of their effect, and in the abolition of their effect by add ition of farnesoic acid (a late precursor of JH) to CA in vitro.