Basis for selective action of a synthetic molting hormone agonist, RH-5992 on lepidopteran insects.
The non-steroidal ecdysone agonist, RH-5992, induces a precocious incomplete molt in lepidopteran insects but is refractory to insects of other orders. We used two lepidopteran cell lines, FPMI-CF-203 (CF-203) and IPRI-MD-66 (MD-66) and two dipteran cell lines, DM-2 and Kc, to investigate the lepidopteran specificity of RH-5992. The mRNAs for hormone receptor 3 homologues cloned from Drosophila (DHR3) and Choristoneura (CHR3) are directly induced by 20-hydroxyecdysone (20E) and serve as suitable markers for studying ecdysone action. Dose response experiments showed that 10(-7) M 20E induced CHR3 mRNA in CF-203 cell and DHR3 mRNA in DM-2 cells. Concentrations of RH-5992 as low as 10(-10) M induced CHR3 mRNA in CF-203 cells, whereas concentrations as high as 10(-6) M induced only very low levels of DHR3 mRNA in DM-2 cells. Studies using 14C-RH-5992 revealed that lepidopteran cell lines (CF-203 and MD-66) retained more of this compound within the cells than the dipteran cell lines (DM-2 and Kc). The clearance of RH-5992 from DM-2 cells was temperature dependent and was blocked by 10(-5) M ouabain, an inhibitor of Na+, K(+)-ATPase suggesting that the efflux was due to active transport.
Sundaram
M
M
Great Lakes Forestry Centre, Canadian Forest Service, Natural Resources Canada, Sault Ste. Marie, Ontario, Canada.
Palli
S R
SR
Krell
P J
PJ
Sohi
S S
SS
Dhadialla
T S
TS
Retnakaran
A
A
D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004175:Diptera; D029721:Drosophila Proteins; D004331:Drosophila melanogaster; D004441:Ecdysterone / Q000819:agonists / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D006834:Hydrazines / Q000493:pharmacokinetics / Q000494:pharmacology*; D007306:Insecticides / Q000494:pharmacology; D007605:Juvenile Hormones / Q000819:agonists; D009036:Moths; D012333:RNA, Messenger / Q000096:biosynthesis; D018160:Receptors, Cytoplasmic and Nuclear / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism
D029721:Drosophila Proteins; C106186:Hr3 protein, Drosophila; D006834:Hydrazines; D007306:Insecticides; D007605:Juvenile Hormones; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D004441:Ecdysterone; C082026:tebufenozide