Manipulation of intracellular calcium affects in vitro juvenile hormone synthesis by larval corpora allata of Manduca sexta.
The effect of altering intracellular free Ca2+ on juvenile hormone (JH) and acid synthesis by larval and pupally-committed corpora allata (CA) of fifth stadium Manduca sexta was investigated. Larval CA required extracellular Ca2+ greater than or equal to 0.1 mM for maximal JH synthesis, while JH acid synthesis by glands after pupal commitment was independent of extracellular Ca2+. Free Ca2+ in the hemolymph ranged from 1.4 to 2.1 mM during the fifth stadium. Both calcium ionophores and caffeine, which releases Ca2+ from intracellular stores, inhibited JH synthesis by larval CA but stimulated JH acid synthesis by post-commitment CA. These results suggest that intracellular stores may be the principal source of Ca2+ for the biosynthetic activity of the post-commitment gland. Calcium channel blockers (La3+, Cd2+) and antagonists (verapamil, isradipine and nitrendipine) decreased both JH and JH acid synthesis, indicating the existence of Ca2+ channels in the CA cell membrane. Calmodulin (CaM) antagonists inhibited the activity of both larval and post-commitment CA, suggesting an integral relationship of CaM to the effects of Ca2+ on gland activity. One of these effects is the demonstrated requirement of 0.1 mM extracellular Ca2+ for allatostatin inhibition of JH I synthesis by larval CA.
Allen
C U
CU
Department of Cell Biology and Anatomy, University of North Carolina, Chapel Hill 27599.
Janzen
W P
WP
Granger
N A
NA
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002147:Calmodulin / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D003335:Corpora Allata / Q000187:drug effects / Q000378:metabolism*; D006458:Hemolymph / Q000737:chemistry; D019476:Insect Proteins; D007605:Juvenile Hormones / Q000096:biosynthesis*; D007814:Larva / Q000187:drug effects / Q000378:metabolism; D009036:Moths / Q000187:drug effects / Q000378:metabolism; D010455:Peptides / Q000502:physiology; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D011863:Radioimmunoassay
D002121:Calcium Channel Blockers; D002147:Calmodulin; D019476:Insect Proteins; D007605:Juvenile Hormones; D010455:Peptides; C071432:allatostatin protein, Manduca sexta; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D002118:Calcium; D011761:Pyrrolidonecarboxylic Acid