JUVENILE-HORMONE DEGRADATION IN THE FEMALE LOCUST (LOCUSTA-MIGRATORIA) - EVIDENCE FOR NEW CATABOLITES

Catabolism of (10R)-[H-3]juvenile hormone III (JH III), the labelled natural enantiomer of JH III was studied in vivo in the adult female Locusta migratoria. Reverse phase liquid chromatography (RPLC) at pH 7.4 coupled with on line radiodetection, revealed JH III acid diol and an unknown compound (X) as major end products of JH III catabolism. RPLC analysis at pH 3 revealed an additional end-product (Z) that comigrates with JH III acid diol at pH 7, Both X and Z lose their carboxyl methyl group and Z was proposed as the diol form of X. A lower rate of in situ degradation for the (10R) enantiomer when compared with racemic JH III was demonstrated when JH degradation was followed quantitatively by using a partition assay. In short-term experiments, inhibition of JH biosynthesis using fluvastatin (an HMG-CoA reductase inhibitor) or surgical allatectomy, increased the rate of disappearance of labelled JH. However, 24 h after allatectomy, the rate of disappearance of the label was similar to that in sham-operated animals, suggesting substantial changes in JH III catabolism in response to the operation.