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Stage-specific production and release of juvenile hormone esterase from the ovary of Diploptera punctata
Ist Teil von
Journal of insect physiology, 2000-05, Vol.46 (5), p.771-782
Ort / Verlag
England: Elsevier Ltd
Erscheinungsjahr
2000
Link zum Volltext
Quelle
Elsevier Journal Backfiles on ScienceDirect (DFG Nationallizenzen)
Beschreibungen/Notizen
Juvenile hormone esterase (JHE) is a catabolic enzyme that specifically degrades juvenile hormone (JH) and has been identified in hemolymph and tissues in both larvae and adults of numerous insect species. This study investigates the presence of JHE in ovaries of the viviparous cockroach, Diploptera punctata, and the in vitro release of JHE from these ovaries during the first gonadotrophic cycle. JHE is released in vitro from maturing basal (most posterior) follicles and from follicle cells isolated from oocytes during the short period of time between spermatophore release and chorion formation. Enzyme release is dependent upon the presence of calcium in the medium. This released ovarian JHE appears to be larger than and to display ionic characteristics that are different from the isolated hemolymph and fat body JHEs. In addition, JHE activity measured in homogenates of whole ovaries and subsequently oviposited basal oocytes increases dramatically following spermatophore release, coincident with a previously described decline in JH titer in the ovary. A likely role for ovarian JHE is the site-specific degradation of JH in and around the oocyte prior to fertilization and embryonic development.