title: Replication of Drosophila chromosomes. IX. Stimulation of initiation of polytene replication cycles in vitro by juvenile hormone.
abstract: A greater proportion of polytene nuclei show [3H]thymidine incorporation when third instar larval salivary glands of Drosophila nasuta are pulse-labelled after in vitro culture (3-24 h) in the presence of a juvenile hormone mimic, ZR 515. In glands chronically labelled with [3H]thymidine in the presence of ZR 515, more nuclei are seen to have entered new polytene replication cycles. Similarly, when salivary glands from larvae fed on 5-fluorodeoxyuridine to block polytene replication cycles at intersynthetic periods were cultured in vitro, new polytene replication cycles were initiated more quickly in the presence of ZR 515. These results suggest a stimulatory effect of juvenile hormone on new polytene replication cycles.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002875:Chromosomes / Q000187:drug effects / Q000502:physiology*; D004261:DNA Replication / Q000187:drug effects*; D004330:Drosophila / Q000502:physiology*; D005467:Floxuridine / Q000494:pharmacology; D007605:Juvenile Hormones / Q000494:pharmacology*; D007700:Kinetics; D008726:Methoprene / Q000494:pharmacology*; D012469:Salivary Glands / Q000187:drug effects / Q000502:physiology
chemical_list: D007605:Juvenile Hormones; D005467:Floxuridine; D008726:Methoprene