A. Dorn
1982
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Influential Citations
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Journal
General and comparative endocrinology
Abstract
Abstract Precocene 2 was used as a tool for uncovering possible juvenile hormone functions during embryogenesis of the milkweed bug Oncopeltus fasciatus . The most conspicuous effect, which was observed after precocene treatment of freshly laid eggs, was the secondary dorsal closure defect (DC-defect). In these embryos growth processes of the ectoderm leading to dorsal closure were disturbed, i.e., the ectoderm (resp. epidermis) failed to replace the amnion in the abdominal dorsum. The critical period for triggering the DC-defect is around 72 hr, a few hours after blastokinesis. This is the time when the endogenous juvenile hormone titer rises and the fine structure of the corpus allatum indicates a synthetic activity in nontreated embryos ( A. Dorn, 1975 , Verh. Deutsch. Zool. Ges , 67 , 85–89). Thus. also during embryogenesis an antiallatotropic action of precocene 2 seems probable. The fact that the DC-defect can be overcome when precocene treatment is followed by application of juvenile hormone 1 supports this assumption. On the grounds of the described experiments it is suggested that endogenous juvenile hormone controls ectodermal (resp. epidermal) growth processes leading to secondary dorsal closure.