Metabolism of. cap alpha. -ecdysone in intermolt land crabs (Gecarcinus lateralis)

Journal Article · Mon Jan 01 04:00:00 EST 1979 · Gen. Comp. Endocrinol.; (United States)

DOI:https://doi.org/10.1016/0016-6480(79)90114-X· OSTI ID:5374866

McCarthy, J F; Skinner, D M

The metabolic fate of ..gamma..-ecdysone was examined in intermolt crabs to elucidate the biochemical pathways as well as the dynamics of ecdysteroid metabolism. At 1 to 24 h after injection of ..cap alpha..(/sup 3/H)ecdysone, metabolits were extracted from each of five tissues and separated by reverse-phase chromatography. Ecdysone metabolism proceeded through (i) sequential hydroxylation at C-20 and C-26, and (ii) formation of glycosidic conjugates of the free ecdysteroids. The conversion of ..cap alpha..- to ..beta..-ecdysone (20-hydroxyecdysone) was very rapid; within 1 to 4 h, over 50% of the radioactivity was present as ..beta..-ecdysone. Further hydroxylation to 20,26-dihydroxyecdysone was less rapid, but continuous over the experimental period. Fractions of each of the three ecdysteroids were conjugated, probably as ..beta..-glycosides. These conjugates comprised 20% of the total radioactivity in the crab, over half of which was concentrated in the midgut gland and hindgut. Free and conjugated ecdysteroids, as well as an extremely polar material which was resistant to enzymatic hyrdrolysis, were excreted in both the urine and the feces. The rate of elimination of total radioactivity and the rate of turnover of ..beta..-ecdysone were fairly rapid but varied among the different tissues. The rate of turnover in the epidermis was very rapid (k approx. 0.08 h/sup -1/). Turnover in the caracass and the whole crab was slower (k approx. 0.02 hr/sup -1/), perhaps due to sequestration of some of the metabolites in tissues which are inactive in the metabolism of ecdysteroids.

• Research Organization: Univ. of Tennessee, Oak Ridge
• OSTI ID: 5374866
• Journal Information: Gen. Comp. Endocrinol.; (United States), Journal Name: Gen. Comp. Endocrinol.; (United States) Vol. 37; ISSN GCENA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
550500 -- Metabolism
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
ARTHROPODS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOCHEMICAL REACTION KINETICS
BLOOD-PLASMA CLEARANCE
BODY
CHEMICAL REACTIONS
CLEARANCE
DECOMPOSITION
ENZYMATIC HYDROLYSIS
EPIDERMIS
EPITHELIUM
EXCRETION
HORMONES
HYDROGEN ISOTOPES
HYDROLYSIS
INVERTEBRATES
ISOTOPES
KINETICS
LABELLED COMPOUNDS
LIGHT NUCLEI
LYSIS
METABOLISM
METABOLITES
NUCLEI
ODD-EVEN NUCLEI
ORGANS
RADIOISOTOPES
REACTION KINETICS
SKIN
SOLVOLYSIS
STEROID HORMONES
TISSUES
TRITIUM
YEARS LIVING RADIOISOTOPES