Fenoxycarb and thyroid hormones have JH-like effects on the follicle cells of Locusta migratoria in vitro.
Earlier work had shown that JH acts on the membrane of the follicle cell of Locusta migratoria, bringing about a rapid reduction in volume which can be detected in vitro by measuring the increase in optical path difference using quantitative interference microscopy. The juvenoid fenoxycarb, a phenoxyphenyl derivative, is unrelated in structure to the juvenile hormones (which are derivatives of farnesoic acid), but it also caused a reduction in volume of the cells in vitro as measured by an increase in the optical path difference. The vertebrate hormone thyroxine, and thyronine, the non-iodinated derivative of thyroxine, also phenoxy phenyl compounds, evoked a response like fenoxycarb. The effect of thyroxine was abolished by ouabain, which inhibits Na+/K+ ATPase, the effector molecule for JH, and inhibited by ethoxyzolamide which inhibits the binding of JH to a putative membrane receptor. Triiodothyronine, the effective vertebrate hormone, acted at a lower threshold and optimum concentration, and had a greater magnitude of effect than the other compounds tested. These facts suggest that these phenoxyphenyl compounds are JH agonists and that the membrane receptor for JH may resemble a possible membrane receptor for thyroxine.
Davey
K G
KG
Department of Biology, York University, North York, Ontario, Canada.
Gordon
D R
DR
D000818:Animals; D002219:Carbamates / Q000494:pharmacology*; D002478:Cells, Cultured; D005260:Female; D006110:Grasshoppers / Q000166:cytology; D007306:Insecticides / Q000494:pharmacology*; D010042:Ouabain / Q000494:pharmacology; D006080:Ovarian Follicle / Q000187:drug effects; D048448:Phenylcarbamates; D012717:Sesquiterpenes / Q000494:pharmacology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors; D013963:Thyroid Hormones / Q000494:pharmacology*; D013970:Thyronines / Q000494:pharmacology; D013974:Thyroxine / Q000494:pharmacology; D014284:Triiodothyronine / Q000494:pharmacology
D002219:Carbamates; D007306:Insecticides; D048448:Phenylcarbamates; D012717:Sesquiterpenes; D013963:Thyroid Hormones; D013970:Thyronines; D014284:Triiodothyronine; D010042:Ouabain; C036585:juvenile hormone III; D000254:Sodium-Potassium-Exchanging ATPase; C052034:fenoxycarb; D013974:Thyroxine