{"doi":"10.17615/gw71-cs37","title":"Regulation of the ecdysteroid titer of Manduca sexta: reappraisal of the role of the prothoracic glands.","abstract":"It is generally accepted that the prothoracic glands of insects produce ecdysone, which is converted by a 20-monooxygenase in peripheral tissues to the major molting hormone, 20-hydroxyecdysone. Incubation in vitro of the prothoracic glands of larval or pupal Manduca sexta in the presence of a hemolymph protein fraction (HPF) increased the ecdysteroid content of the medium almost 8-fold. A comparable increase was noted when HPF was added to medium preconditioned with prothoracic glands but from which the glands had been removed. We used a differential RIA to show that a major product of the prothoracic glands in vitro cross-reacts with antiserum (20-hydroxyecdysone-2-succinylthyroglobulin amide; H-2) that retains affinity to ecdysteroids having a modified A ring. However, this product did not bind to antiserum (ecdysone-22-succinylthyroglobulin amide; H-22) that has affinity mainly for ecdysteroids modified at the side chain. We employed radiolabeled precursor studies with prothoracic glands in vitro and a combination of analytical techniques (NMR, CD, MS) to demonstrate that the major ecdysteroid release from the glands is a mixture of 2-dehydroecdysone and 3-dehydroecdysone (1:2), which is rapidly reduced to ecdysone in the presence of HPF. We postulate that the active component of HPF is 3 beta 3 beta (2 beta)-formin-3(2)-ketoecdysteroid reductase. These results may explain several anomalous observations pertaining to the molting of insect fragments in the absence of prothoracic glands and suggest a complex system for the control of insect molting and metamorphosis.","journal":"UNC Libraries","year":2020,"id":112185,"datarank":0.0,"base_score":0.0,"endowment":0.0,"self_citation_contribution":0.0,"citation_network_contribution":0.0,"self_endowment_contribution":0.0,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":4,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.953,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2020-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":532533,"name":"S. S. Lee","orcid":null,"position":1,"is_corresponding":false},{"id":532534,"name":"S. Sakurai","orcid":null,"position":2,"is_corresponding":false},{"id":400907,"name":"L. I. Gilbert","orcid":null,"position":3,"is_corresponding":false},{"id":400912,"name":"J. T. Warren","orcid":null,"position":4,"is_corresponding":false},{"id":532535,"name":"D. B. Rountree","orcid":null,"position":5,"is_corresponding":false},{"id":143827,"name":"K. NAKANISHI","orcid":null,"position":0,"is_corresponding":true}],"reference_count":0,"raw_metadata":null,"created_at":"2026-07-18T23:13:13.874980Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}