{"doi":"10.1677/joe.0.0600027","title":"KINETIC STUDIES ON THE ENZYMES CATALYSING THE CONVERSION OF 17α-HYDROXY-PROGESTERONE AND DEHYDROEPIANDROSTERONE TO ANDROSTENEDIONE IN THE HUMAN ADRENAL GLAND IN VITRO","abstract":"<jats:title>SUMMARY</jats:title>\n<jats:p>Factors controlling the synthesis of androstenedione in the human adrenal gland were investigated in a kinetic study of the enzymes catalysing the conversion of 17α-hydroxyprogesterone and dehydroepiandrosterone to the hormone. Both reactions are associated with the microsomal fraction of the adrenal cell. 17α-Hydroxyprogesterone is converted to androstenedione by a NADPH-dependent 17-desmolase whereas there is an obligatory requirement for NAD<jats:sup>+</jats:sup> for the conversion of dehydroepiandrosterone to the hormone. None of the other cofactors investigated inhibited or enhanced the enzymic conversions.</jats:p>\n<jats:p>The side-chain cleavage of 17α-hydroxyprogesterone was competitively inhibited by the precursors of the substrate, pregnenolone, progesterone and 17α-hydroxypregnenolone. Other C<jats:sub>19</jats:sub> or C<jats:sub>18</jats:sub> compounds known to be synthesized by the human adrenal gland were found to be ineffective in modifying the enzyme action. The conversion of dehydroepiandrosterone to androstenedione was non-competitively inhibited by oestrone and oestradiol-17β. No C<jats:sub>21</jats:sub> compounds were found to affect the reaction. 5α-Dihydrotestosterone (17β-hydroxy-5α-androstan-3-one) inhibited both enzymic conversions competitively but the inhibition constants observed were so high that it is unlikely that this finding has any relevance to the control of androstenedione synthesis <jats:italic>in vitro.</jats:italic></jats:p>","journal":"Journal of Endocrinology","year":1974,"id":23328,"datarank":2.9923674123304957,"base_score":3.5553480614894135,"endowment":3.5553480614894135,"self_citation_contribution":0.5333022092234121,"citation_network_contribution":2.4590652031070834,"self_endowment_contribution":0.5333022092234121,"citer_contribution":2.4590652031070834,"corpus_percentile":null,"corpus_rank":null,"citation_count":34,"citer_count":32,"citers_with_citation_signal":31,"citers_with_endowment":31,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":null,"is_data_producer":false,"deposit_databanks":null,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":null,"fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":143596,"name":"N. DESHPANDE","orcid":null,"position":1,"is_corresponding":false},{"id":143595,"name":"JEAN YATES","orcid":null,"position":0,"is_corresponding":false}],"reference_count":0,"raw_metadata":{"has_enrichment":true,"base_score":3.5553480614894135,"endowment":3.5553480614894135,"datacite_reuse_total":0,"file_count":0,"downloads":0,"views":0,"has_version_chain":false,"is_dataset":false,"is_oa":false,"pmid":"4149619","pmcid":null,"openalex_id":"https://openalex.org/W2061449132","authors":[],"funders":[],"total_grants":0,"fwci":0.7048,"citation_percentile":0.69910931,"influential_citations":0,"citation_trend":[{"year":2016,"count":1},{"year":2026,"count":1}],"oa_status":"closed","license":null,"oa_locations":[{"url":"https://joe.bioscientifica.com/view/journals/joe/60/1/joe_60_1_004.xml","host_type":"publisher"},{"url":"https://joe.bioscientifica.com/downloadpdf/journals/joe/60/1/joe_60_1_004.xml","host_type":"publisher"},{"url":"https://doi.org/10.1677/joe.0.0600027","host_type":"journal"},{"url":"https://pubmed.ncbi.nlm.nih.gov/4149619","host_type":"repository"}],"fields_of_study":["Hormonal and reproductive studies","Steroid Chemistry and Biochemistry","Estrogen and related hormone effects","Biology","Medicine","17-alpha-Hydroxypregnenolone","Adrenal Glands","Androstenedione","Dehydroepiandrosterone","Depression, Chemical","Estradiol","Estrone","Female","Humans","Hydroxyprogesterones","Hydroxysteroid Dehydrogenases","Kinetics","Microsomes","NAD","NADP","Oxidoreductases","Pregnenolone","Progesterone"],"mesh_terms":["Adrenal Glands","Androstenedione","Dehydroepiandrosterone","Depression, Chemical","Estradiol","Estrone","Female","Humans","17-alpha-Hydroxypregnenolone","Hydroxyprogesterones","Hydroxysteroid Dehydrogenases","Kinetics","Microsomes","NAD","NADP","Oxidoreductases","Pregnenolone","Progesterone"],"keywords":["Androstenedione","Dehydroepiandrosterone","Pregnenolone","Internal medicine","Endocrinology","Chemistry","Enzyme","Adrenal gland","Estrone","Microsome","Hormone","In vitro","Testosterone (patch)","Steroid","Biochemistry","Androgen","Biology","Medicine"],"sdg_mappings":[{"sdg_number":0,"sdg_label":"Clean water and sanitation"}],"linked_datasets":[],"clinical_trials":[],"software_tools":[],"database_accessions":[],"source":"live","citation_network_status":"fetched"},"created_at":"2026-06-07T19:11:00.667007Z","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":[]}