Allatostatic peptides from brains

The allatostatins are a family of brain peptides which rapidly and reversibly inhibit juvenile hormone biosynthesis in isolated insect corpora allata. Five allatostatic peptides from brains of the cockroach Diploptera punctata have now been structurally identified (i 2 our unpublished results), their size ranging from octapeptide to octadecapeptide. The currently identified allatostatins all possess the consensus C-terminal sequence (L/V)YXFGL-amide, which has no significant homology with other known peptides. It is likely that they are released locally from nerve terminals within the glands (3). 

Allatostatic peptides from brains of Diploptera punctata biological activity, 188,189/ control of sample loss, 178-179 dose-response curves for biological activity, 188,189/ effect of N-terminal truncation on activity, 191-192... 

Pratt et al. (20) have isolated and sequenced allatostatin 1 from the brain of adult female p. punctata using isolation procedures different from ours and also indicated that other allatostatins remain to be identified. With yet other methods Khan, Guan and Tobe (unpublished) also isolated and sequenced allatostatin 4 from extract of Q. punctata adult brain. It will now be important to determine whether these peptides occur and act as allatostatins in other groups of insects. The corpora allata of . americana are also inhibited by allatostatin 1 (16). Since P. americana is not closely related to D. punctata (21), it is likely that these allatostatins will be functional in other species of cockroaches. A cerebral allatostatic factor from last instar larval Manduca sexta inhibits JH I synthesis by CA 1b vitro (22). This factor is characterized as a protein of much higher... 

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