Isolation and identification of 20‐hydroxyecdysone from a lepidopteran continuous cell line

Abstract

AbstractExtracts of three continuous cell lines from the cabbage looper, Trichoplusia ni, were assayed for the presence of ecdysteroids. While no evidence of ecdysteroids was present in the extracts of the ovarian (TN‐368) or embryonic (IPLB‐TN‐R2) cell lines, radioimmunoassays on extracts of media and extracts of cell pellets from imaginal disc cell cultures (IAL‐TND1) were positive. The immunoreactive material from both cells and media co‐migrated with a 20‐hydroxyecdysone standard on reversed‐phase high‐performance liquid chromatography (HPLC). The immunoreactive fractions from the cell extract were chromatographed on silica HPLC and subjected to mass spectral analysis. Both of these analyses indicated that the unknown compound was 20‐hydroxyecdysone. Radioimmunoassay indicated up to 28 ng of ecdysone equivalents in cells (3.75 x 107 cells) from 50 ml of IAL‐TND1 cultures, which is equivalent to 120 ng of 20‐hydroxyecdysone based on relative reactivity of the antiserum used in this study. This report presents the first evidence of 20‐hydroxyecdysone production by a continuous insect cell line and also the first to show that cells from imaginal discs are capable of ecdysteroid synthesis.