Formation of apolar ecdysteroid conjugates by ovaries of the house cricket Acheta domesticus in vitro.

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Formation of apolar ecdysteroid conjugates by ovaries of the house cricket Acheta domesticus in vitro.

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dc.contributor.author Whiting, P en_GB
dc.contributor.author Dinan, L en_GB
dc.date.accessioned 2007-05-17T14:48:39Z en_GB
dc.date.accessioned 2011-01-25T11:46:56Z en_US
dc.date.accessioned 2013-03-20T14:48:08Z
dc.date.issued 1988-05-15 en_GB
dc.description.abstract The newly laid eggs of the house cricket Acheta domesticus contain apolar ecdysteroid conjugates, which we have hypothesized to be ecdysone long-chain fatty acyl esters [Whiting & Dinan (1988) J. Insect Physiol., in the press]. The ovaries of mature adult female A. domesticus in vitro convert [3H]ecdysone into apolar conjugates identical with those found in newly laid eggs. Comparison of the radioactive metabolites produced on incubation of [3H]ecdysone with various organs of adult female A. domesticus in vitro indicate that the fat-body is the major producer of polar ecdysteroid metabolites at this stage of development, whereas the ovaries are the major site of production of apolar metabolites. Apolar metabolites are also produced to a lesser extent by the crop, gut sections and the fat-body. Hydrolysis of radioactive metabolites produced by the ovaries with Helix enzymes releases only [3H]ecdysone, and thus ecdysone is not metabolized before conjugation by the ovaries. Formation of chemical derivatives (acetonide and acetates) of these 3H-labelled apolar conjugates strongly indicates that the position of conjugation is through the hydroxy group at C-22 of ecdysone. Extensive chromatographic analysis of the 3H-labelled apolar metabolites produced by the ovaries by t.l.c. and h.p.l.c. and comparison with authenticated reference compounds have conclusively demonstrated that the conjugates consist of ecdysone esterified at C-22 to a mixture of common long-chain fatty acids. The major fatty acyl esters have been identified and their percentage contribution to the mixture determined: laurate (0.5%), myristate (2.8%), palmitate (25.8%), stearate (8.4%), arachidate (1.0%), oleate (15.7%), linoleate (38.8%) and linolenate (2.1%). In addition there are three minor unidentified peaks, one of which has been tentatively identified as ecdysone 22-palmitoleate (2.6%). Comparison of this percentage composition with the previously published fatty acid composition of A. domesticus haemolymph [Wang & Patton (1969) J. Insect Physiol. 15, 851-860] reveals remarkable similarities, indicating that the acyl transferase(s) forming the conjugates have a broad specificity with regard to the fatty acyl substrate. en_GB
dc.identifier.citation Biochemical Journal, 1988, 252(1):95-103 en_GB
dc.identifier.uri http://hdl.handle.net/10036/11929 en_GB
dc.language.iso en_US en_GB
dc.title Formation of apolar ecdysteroid conjugates by ovaries of the house cricket Acheta domesticus in vitro. en_GB
dc.type Article en_GB
dc.date.available 1988-05-15 en_GB
dc.date.available 2007-05-17T14:48:39Z en_GB
dc.date.available 2011-01-25T11:46:56Z en_US
dc.date.available 2013-03-20T14:48:08Z
dc.identifier.issn 0264-6021 en_GB
dc.identifier.issn 1470-8728 en_GB
dc.format.dig YES en_GB
dc.identifier.journal Biochemical Journal en_GB
dc.identifier.pmcid 1149111 en_GB
dc.identifier.pmid 3421912 en_GB


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