Investigation of the endocrine system in extended longevity lines of Drosophila melanogaster

There is a complete absence of information about the endocrinology of Droso phila melanogaster in relation to genetic-based differential longevity in t his model species. In the present study, aspects of the endocrine system of D. melanogaster were investigated in selected and control lines characteri zed by relative differences in life span. By using extracts from whole bodi es, steroid hormone (ecdysteroid) titers were determined by radioimmunoassa y in all replicate selected and control lines on the first and fourth day o f adult life. The results suggest that ecdysteroid titers were relatively r educed on the first day post-eclosion in females from the long-lived lines, but this difference was not present on the fourth day posteclosion. The re duction in early-age ecdysteroid titers in long-lived females might be rela ted to the decrease in early-age fecundity in the selected lines. There was no difference between line types in male ecdysteroid titers on either day posteclosion. Two classes of enzymes that act on juvenile hormone were also investigated in the present study. Esterase and epoxide hydrolase activity on juvenile hormone was assessed in females in all replicate selected and control lines at approximately 12 h or 4 days pot-eclosion. There was no di fference between selected and control lines in the specific activity of eit her class of enzymes that metabolize juvenile hormone. (C) 1999 Elsevier Sc ience Inc. All rights reserved.