Insect tissue culture systems: models for study of hormonal control of development

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 incubation in L-15B medium supplemented with 10% fetal bovine serum (FBS) and 10% cockroach hemolymph, adult male corpora allata exhibited a cycle of de novo DNA synthesis followed by cell division. The number of S-phase cells and metaphase cells per corpus allatum were counted from whole-mount monolayers after labeling in vitro with 5'-bromo-2'-deoxyuridine 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-specific and adult female hemolymph was more potent than hemolymph from adult males. Furthermore, DNA synthesis of corpus allatum cells was stimulated in vitro by 20-hydroxyecdysone. This sensitive assay system will be of immense utility in the search for allatal growth factors.