AUTOINHIBITION OF JUVENILE-HORMONE PRODUCTION - THE CASE OF THE COCKROACH BLATTELLA-GERMANICA (L)

In 6-day-old females of Blattella germanica, the activity of corpora a llata (CA) was inhibited in vitro by juvenile hormone III (JH III). Ef fective doses (281.5 and 375.4 muM in the medium) were somewhat higher than (although of the same order of magnitude as) the estimated intra glandular concentration of JH III at this age, and they induced about 45% inhibition of hormonal release and a significant intraglandular ac cumulation of JH III and methyl farnesoate. The results suggest that a utoinhibitory mechanisms operate in the CA to constrain the upper limi t of JH III production at the end of the gonadotrophic cycle.