HoDGE[1] reported the determination of lipids in human gingiva. FISHER et al.[2] investigated into the cholesterol contents in bovine and human gingiva. STERN et al.[3] observed the incorporation of sodium acetate-1-14C into cholesterol, palmitic acid and oleic acid in human gingiva. OTAKE et al.[4] also reported the incorporation of sodium acetate-1-14C into the lipid fractions in guinea pig gingiva. Recently, KANDA[5] reported the incorporation of radioactivity from sodium acetate-1-14C into the lipid fractions in gingiva of guinea pig fed on ascorbic acid deficient diet, and incorporated radioactivity in the free fatty acid fraction of scorbutic animals was increased about twice than that of normal. However, no work has been done to study the patterns of fatty acid biosynthesized in scorbutic guinea pig gingiva.
The present report describes the patterns of free fatty acids biosynthesized from sodium acetate-1-14C in scorbutic guinea pig gingiva.
Sodium acetate-1-14C (specific activity : 45.4 mCi/mM) was obtained from New England Corp. Other materials were also available commercially. Compressed diet RC5 for the experimental animals was obtained from Oriental Yeast Industrial Company, Ltd. Male guinea pig, weighing from 300 to 350 g were used. The animals were fed on a scorbutogenic diet for 23 days. The diet was prepared by heat treatment of the compressed diet RC5 at 100°C for 2 hours. The animals were killed by decapitation, and gingiva was quickly excised and placed in ice-cold 0.25 M sucrose solution. Sixty mg of gingiva was incubated at 37°C for 3 hours in 2.0 ml of the Krebs-Ringer phosphate buffer (pH 7.4) containing 100 μCi of sodium acetate-1-14C. The tissue was removed from the reaction mixture was washed with 3 x 100 ml of distilled water. Then, the tissue was homogenized with 10 ml of chloroform-methanol (2:1), and the lipids were extracted for 20 hours at room temperature. The organic phase was separated by centrifugation, and the precipitate was washed 20 ml of the same organic solvent. The combined organic solvent was dried under a nitrogen
The evidence suggested that in gingiva of the scorbutic animals, biosynthesis of unsaturated fatty acid of C18 is inhibited but that of saturated fatty acid of C18is stimulated.
