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Distribution and Regulation of Esterases That Hydrolyze Methyl Farnesoate inHomarus americanusand Other Crustaceans

1997; Elsevier BV; Volume: 106; Issue: 1 Linguagem: Inglês

10.1006/gcen.1996.6850

1095-6840

Ellen Homola, Ernest S. Chang,

Neurobiology and Insect Physiology Research

Ester hydrolysis of methyl farnesoate (MF) by crustacean tissue homogenates was measured using the substrate [3H]MF in a radiochemical partition assay. Tissues were obtained from the lobsterHomarus americanus,penaeid shrimpSicyonia ingentis,thalanassid shrimpCallianassa californiensis,sand crabEmerita analoga,and spider crabPugettia producta.The greatest specific activities were recovered from the hepatopancreas (239 to 11,500 pmol MF/min-mg total protein). Hepatopancreatic homogenates ofC. californiensiswere significantly more active than homogenates from the other species. In the lobster, esterases that hydrolyze MF were associated with lipid storage (R) cells of the hepatopancreas. Enzyme activity of lobster larval homogenates increased 1.5-fold during the second stage of development. The rate of MF hydrolysis by esterases extracted from the juvenile lobster hepatopancreas could not be correlated with molt stage or sex and was not significantly influenced by eyestalk ablation, mandibular organ ablation, or MF injection.