ISSN:
1420-9071
Keywords:
Ecdysteroid receptor
;
prothoracicotropic hormone
;
neuroendocrine-endocrine axis
;
feedback regulation
;
autoradiography
;
immunocytochemistry
;
Manduca sexta
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract With a combination of thaw-mount autoradiography using a tritiated 20-hydroxyecdysone agonist, ponasterone A, and immunocytochemistry with a monoclonal antibody to 29 K-prothoracicotropic hormone, high affinity binding sites for ecdysteroids were identified in the tissues of the neuroendocrine-endocrine axis inManduca sexta larvae. At specific times during larval-pupal development in fifth stadium larvae, nuclear ecdysteroid binding sites were present in the cerebral prothoracicotropes, the corpora allata and prothoracic glands, the main axis for the regulation and production of ecdysteroids. A stage-specific appearance of ecdysteroid receptors also occurred in cells of fat body, midgut and Malpighian tubules, tissues which convert ecdysone into 20-hydroxyecdysone. Our data identify new target tissues for ecdysteroids and suggest that ecdysteroids could affect their own production at the genomic level via long and short feedback loops.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01923604
