IN-VITRO GROWTH OF CORPORA ALLATA FROM DIPLOPTERA-PUNCTATA

An in vitro organ culture system was established to support growth of corpora allata from the cockroach Diploptera punctata. During a 1-wk i ncubation in L-15B medium supplemented with 10% fetal bovine serum (FB S) and 10% cockroach hemolymph, adult male corpora allata exhibited a cycle of de novo DNA synthesis followed by cell division. The number o f S-phase cells and metaphase cells per corpus allatum were counted fr om whole-mount monolayers after labeling in vitro with 5'-bromo-2'-deo xyuridine and exposure to colchicine, respectively. While both FBS and cockroach hemolymph were essential for proliferation of allatal cells , the growth-promoting effect of insect hemolymph was not species-spec ific and adult female hemolymph was more potent than hemolymph from ad ult males. Furthermore, DNA synthesis of corpus allatum cells was stim ulated in vitro by 20-hydroxyecdysone. This sensitive assay system wil l be of immense utility in the search for allatal growth factors.