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In an insect, the tobacco hornworm Manduca sexta, the cerebral neuropeptide prothoracicotropic hormone (PTTH), the primary effector of postembryonic development, exists as two molecular forms. These two PTTH's elicit characteristic in vitro dose responses of activation of prothoracic glands from different developmental stages, an indication that during(More)
A modified in vitro assay was used to assess the kinetics of activation and the decay of activation of the prothoracic glands (PG) by the prothoracicotropic hormone (PTTH) in Manduca sexta. Time-courses of ecdysone synthesis by PTTH-activated day 3 larval and day 0 pupal PG were comparable both quantitatively and temporally, but dose-responses of PTTH(More)
Immunocytochemistry revealed that a Bombyx mori prothoracicotropic hormone (PTTH)-like peptide is expressed by the Manduca sexta big PTTH-producing neurons, the lateral neurosecretory cell group III (L-NSC III). Independent PCR of genomic DNA and a L-NSC III cDNA library yielded products with 99% sequence similarity to the cDNA encoding Bombyx PTTH. This(More)
The prothoracicotropic hormone (PTTH) is an insect cerebral peptide that stimulates the prothoracic glands to produce the steroid hormone ecdysone thus initiating molting and metamorphosis. "Big" PTTH, one of several molecular forms of the neurohormone, was isolated from brains of the tobacco hornworm Manduca sexta, and fractionated by high-pressure liquid(More)
The prothoracicotropic hormones (PTTHs) are cerebral peptides that control insect postembryonic development by stimulating the prothoracic glands to synthesize ecdysteroids. In Manduca sexta, the tobacco hornworm, two classes of PTTH are distinguished by their M(r), small (ca. 7 kDa) and big PTTH (ca. 25-30 kDa). Little is known about the physical nature of(More)
The prothoracicotropic hormones (PTTH) are cerebral peptides that control insect postembryonic development by stimulating the prothoracic glands to synthesize ecdysteroids. Using immunoaffinity chromatography and SDS-PAGE, a 25.5 kDa big PTTH has been purified from Manduca sexta. Based upon SDS-PAGE and Western blot analysis, the native form of big PTTH(More)
1. A 28-kDa peptide from the brain of the tobacco hornworm, Manduca sexta, was purified via HPLC. The peptide copurified with the insect neurohormone, prothoracicotropic hormone (PTTH), through two HPLC columns. 2. Immunocytochemistry using polyclonal antibodies against the 28-kDa peptide revealed that the peptide was produced in the same protocerebral(More)
A larval moult in the tobacco hornworm, Manduca sexta, involves an endocrine cascade that begins with the release of a cerebral peptide hormone, the prothoracicotropic hormone (PTTH). The release of PTTH is gated, occurs during the scotophase and appears to be developmentally cued. In fourth instar Manduca larvae, PTTH release into the haemolymph occurs as(More)
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