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Metabolism and tissue distribution of label from [9,10‐methylene‐ 14 C] sterculic acid in the rat
Author(s) -
Nixon J. E.,
Yoss J. K.,
Eisele T. A.,
Pawlowski N. E.,
Sinnhuber R. O.
Publication year - 1977
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/bf02533756
Subject(s) - cyclopropene , metabolism , chemistry , fatty acid , methylene , methylene blue , excretion , medicine , microsome , intraperitoneal injection , endocrinology , biochemistry , biology , medicinal chemistry , enzyme , photocatalysis , catalysis
The metabolism of 14 C‐sterculic acid, labeled in the methylene carbon of the cyclopropene ring, was investigated in Wistar rats. Comparison of the distribution of radioactivity in tissue and excreta as a function of time showed that the free sterculic acid was metabolized faster than the methyl ester and that the sterculic acid administered by intragastric intubation was absorbed and metabolized at a faster rate than that administered by intraperitoneal injection. The concentration of label in blood serum reached a maximum 2 hr after intubation and then rapidly declined. Incorporation of radioactivity into most organs peaked at 4 hr with liver peaking at a maximum of 11% of the administered dose and other organs at less than 1%. Label in depot fat steadily increased to 8% at 26 hr. Less than 1% of the administered dose was expired in CO 2 in the same time period. Excretion of label reached a maximum of 48% in urine and 11% in feces by 16 hr. The majority of the label in liver was in the fatty acid portion of the lipid fraction. The relative amount of label in microsomal and mitochondrial subcellular fractions of liver changed with time suggesting that these organelles may be involved in the metabolism of sterculic acid. Rats fed control diets appeared to metabolize sterculic acid in the same manner, but at a slower rate than rats acclimated to dietary cyclopropene fatty acids. Low recovery of label in expired air showed that the methylene carbon of the cyclopropene ring was not oxidized to CO 2 . These data suggest that rats readily absorb sterculic acid and excrete labeled compounds primarily in the urine.