The means by which hormones interact and control growth and development will be examined using insert metamorphosis as a model system. Precisely timed tobacco hornworm larvae raised on an artificial diet will be the primary experimental organisms. We will attempt to purify and characterize the two forms of the brain neurohormone (PTTH) that initiate cellular reporgramming and the molting cycle, using chromatographic and electrophoretic methods and our newly devised specific and sensitive in vitro assay. Once purified, will be generated and an RIA will be developed so as to titer the hormone and immunocytochemically trace its transport from the site of synthesis (prothoracicotropes) to the neurohemal organ. The role of PTTH in stimulating the prothoracic glands to synthesize and secrete ecdysone, via cAMP, will be studied using organ culture techniques to quantify protein kinase activity (protein phosphorylation). ACtive and inactive prothoracic glands will be investigated as well as glands stimulated by crude extracts and purified PTTH. The role of PTTH in embryogenesis, pupal diapause, and diapause-break will also be explored. Studies will continue on the regulation of the mitochondrial cytochrome P450 ecdysone monooxygenase that converts the steroid prohormone, ecdysone, to the molting hormone, 20-hydroxyecdysone, with emphasison control by juvenile hormone and neural-factors, using our sensitive radioenzymological assay. We will investigate the relationship between the very specific juvenile hormone binding protein of insect hemolymph and target cell cytosol receptors utilizing competitive binding protein techniques developed in this laboratory. Using very high specific activity tritiated ecdysteroid and nominally high specific activity juvenile hormone, receptors for both hormone classes will be localized in endocrine gland so as to examine feedback relationships between the glands and the growth hormones. These studies should provide evidence for the means by which animals regulate and maintain hormone titers and how environment cues are transduced into endocrine mediated events. These phenomena could shed light on endocrinologically based diseases and may lead to new concepts for insect control, insects being vectors of numerous human diseases and the indirect cause of malnutrition.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK030118-06
Application #
3229285
Study Section
Endocrinology Study Section (END)
Project Start
1981-06-01
Project End
1986-12-31
Budget Start
1986-01-01
Budget End
1986-12-31
Support Year
6
Fiscal Year
1986
Total Cost
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Type
Schools of Arts and Sciences
DUNS #
078861598
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Warren, J T; Wismar, J; Subrahmanyam, B et al. (2001) Woc (without children) gene control of ecdysone biosynthesis in Drosophila melanogaster. Mol Cell Endocrinol 181:1-14
Baker, K D; Warren, J T; Thummel, C S et al. (2000) Transcriptional activation of the Drosophila ecdysone receptor by insect and plant ecdysteroids. Insect Biochem Mol Biol 30:1037-43
Rybczynski, R; Gilbert, L I (2000) cDNA cloning and expression of a hormone-regulated heat shock protein (hsc 70) from the prothoracic gland of Manduca sexta. Insect Biochem Mol Biol 30:579-89
Dai, J D; Gilbert, L I (1999) An in vitro analysis of ecdysteroid-elicited cell death in the prothoracic gland of Manduca sexta. Cell Tissue Res 297:319-27
Henrich, V C; Rybczynski, R; Gilbert, L I (1999) Peptide hormones, steroid hormones, and puffs: mechanisms and models in insect development. Vitam Horm 55:73-125
Warren, J T; Dai, J D; Gilbert, L I (1999) Can the insect nervous system synthesize ecdysteroids? Insect Biochem Mol Biol 29:571-9
Rybczynski, R; Gilbert, L I (1998) Cloning of a beta1 tubulin cDNA from an insect endocrine gland: developmental and hormone-induced changes in mRNA expression. Mol Cell Endocrinol 141:141-51
Song, Q; Gilbert, L I (1998) Alterations in ultraspiracle (USP) content and phosphorylation state accompany feedback regulation of ecdysone synthesis in the insect prothoracic gland. Insect Biochem Mol Biol 28:849-60
Song, Q; Alnemri, E S; Litwack, G et al. (1997) An immunophilin is a component of the insect ecdysone receptor (EcR) complex. Insect Biochem Mol Biol 27:973-82
Kim, A J; Cha, G H; Kim, K et al. (1997) Purification and characterization of the prothoracicotropic hormone of Drosophila melanogaster. Proc Natl Acad Sci U S A 94:1130-5

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