title: Methyl farnesoate stimulates ecdysteroid secretion from crab Y-organs in vitro.
abstract: Methyl farnesoate (MF) stimulation of ecdysteroid secretion by Y-organs of the crab, Cancer magister, is demonstrated. Isolated Y-organs that were incubated with a mandibular organ (MO) secreted significantly higher levels of ecdysteroids into the medium when compared to those incubated in the absence of a MO. MOs secrete both farnesoic acid (FA) and MF into the medium and are not themselves a source of ecdysteroids. To determine if MF has a role in the regulation of ecdysteroid secretion, Y-organs from C. magister were incubated with various concentrations of MF. Y-organs in the presence of MF secreted significantly more ecdysteroids into the medium after a 24-hr incubation when compared to controls (P < or = 0.05). The magnitude of this stimulation increased with higher concentrations of MF and increasing incubation times. The response was specific to (2E,6E)-MF. The cis,trans isomer of MF ((2Z,6E)-MF), FA, and farnesyl diazomethyl ketone, a photoaffinity analog of MF, did not have any effect on ecdysteroid secretion from Y-organs. The primary ecdysteroid secreted by C. magister Y-organs comigrates with authentic ecdysone and its secretion is stimulated by MF.
authors.affiliation: Bodega Marine Laboratory, University of California, Bodega Bay 94923.
authors.forename: S L
authors.initials: SL
authors.lastname: Tamone
authors.forename: E S
authors.initials: ES
authors.lastname: Chang
mesh_terms: D000345:Affinity Labels; D000818:Animals; D003386:Brachyura / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004440:Ecdysone / Q000378:metabolism; D004702:Endocrine Glands / Q000187:drug effects / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology*; D066298:In Vitro Techniques; D007447:Invertebrate Hormones / Q000378:metabolism*; D008297:Male; D011863:Radioimmunoassay; D013268:Stimulation, Chemical
chemical_list: D000345:Affinity Labels; D005231:Fatty Acids, Unsaturated; D007447:Invertebrate Hormones; C032429:methyl farnesoate; D004440:Ecdysone