Synthesis of apolar ecdysone esters by ovaries of the cockroach Periplaneta americana.
Ecdysteroid levels detected by RIA in extracts of mature ovaries from Periplaneta americana increased approximately fourfold (53 +/- 10 to 184 +/- 38 ng/g; +/- SEM, n = 3) on treatment with Helix pomatia "sulphatase" enzymes. HPLC analysis showed that this increase in immunoreactivity resulted from the hydrolysis of six apolar compounds that cochromatographed with the ecdysteroid esters previously shown to be present in newly laid oothecae (A1, A2, A3, A4, A5, and A6; A. J. Slinger, L. N. Dinan, and R. E. Isaac (1986). Insect Biochem. 16 (i), 115-119). Intact ovaries cultured in saline were able to take up [3H]ecdysone from the medium and synthesize ecdysone esters, most of which cochromatographed with immunoreactive peaks from ovaries and oothecae. Crude homogenates and membranes prepared from mature ovaries were also able to esterify ecdysone in vitro. The enzyme activity associated with a high-speed pellet was greatly enhanced by the addition of coenzyme A fatty acyl esters, each reaction resulting in the synthesis of a single major metabolite. The three esters formed on incubating ecdysone with coenzyme A-palmitate, -lineate, and -oleate could be characterized by their retention times on HPLC which were identical to compounds A2, A5, and A6, respectively. These compounds were the three quantitatively important immunoreactive esters found in ovaries and newly laid oothecae. The data presented indicates that ovaries can esterify ecdysone with palmitic, linoleic, and oleic acids and that these apolar derivatives are transferred to the egg. The esters appear to be different from the ecdysone 22-fatty acyl esters that have been isolated from ticks and other insects.
Slinger
A J
AJ
Department of Pure and Applied Zoology, University of Leeds, England.
Isaac
R E
RE
D000214:Acyl Coenzyme A / Q000378:metabolism; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003058:Cockroaches / Q000378:metabolism*; D004440:Ecdysone / Q000378:metabolism*; D026461:Ecdysteroids; D004441:Ecdysterone / Q000378:metabolism; D004951:Esterification; D005229:Fatty Acids, Monounsaturated; D005260:Female; D007447:Invertebrate Hormones / Q000378:metabolism; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000378:metabolism; D019301:Oleic Acid; D009829:Oleic Acids / Q000378:metabolism; D010053:Ovary / Q000378:metabolism; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism; D010526:Periplaneta / Q000378:metabolism*; D011863:Radioimmunoassay; D013229:Stearic Acids / Q000378:metabolism
D000214:Acyl Coenzyme A; D026461:Ecdysteroids; D005229:Fatty Acids, Monounsaturated; D007447:Invertebrate Hormones; D008041:Linoleic Acids; D009829:Oleic Acids; D010169:Palmitic Acids; D013229:Stearic Acids; C008757:palmitoleic acid; D019301:Oleic Acid; D019308:Palmitic Acid; D004440:Ecdysone; C031183:stearic acid; D004441:Ecdysterone; D019787:Linoleic Acid