Ecdysteroid Production by a Continuous Insect Cell Line

The spent medium from ten established cell lines was extracted and tested for ecdysteroids by radioimmunoassay. Of t h e seven lepidopteran lines tested, only IAL-TNDI and MRRL-CH showed evidence of ecdysteroid production. However, t h e results were erratic and difficult to evaluate and these lines were dropped from further consideration. However, of t h e three cockroach cell lines tested, one, UMBGE 4, produces ecdysteroid and consistently releases virtually all of it into t h e medium. The main ecdysteroid was identified as ecdysone and t h e increase was logarithmic during t h e first 11 days of t h e subculture, with a decrease from day 11 t o day 14. UMBGE 4 is a vesicle cell line which also tested positive for chitin synthesis. When t h e pH of t h e medium was lowered from pH 7.4 t o pH 6.3, both t h e chitin synthesis and t h e ecdysone synthesis dropped by roughly 50%.