Metabolism of [3H]gibberellin A4 in somatic suspension cell cultures of carrot

The native gibberellin A₄ (GA₄), in radioactive form (1,2-³H]GA₄, 1.06 Ci/mmol), was fed to carrot somatic cell cultures (suspension and immobilized cell systems) and its metabolism over a 48 hr period was investigated. It was found that the ³H]GA₄ was metabolized to at least two GAs, ³H]GA₁ and ³H]GA₈, six GA glucosyl conjugates, ³H]GA₁-0(3)-glucoside, ³H]GA₁-0(13)-glucoside, ³H]GA₁-glucosyl ester, ³H]GA₄-glucoside, ³H]GA₄-glucosyl ester, a ³H]GA₈ glucosyl conjugate(s) and a previously unknown ³H]GA₁ glucosyl conjugate (³H]GA₁-0(3,13)-diglucoside-like compound). The GA₁-diglucoside-like compound was found only in extracts of cells and was present in significant amounts (33 % of total extractable radioactivity). All other metabolites were present in both cells and medium. For extracts of the medium, no differences between the suspension and immobilized cultures existed in types of ³H]GA₄ metabolites although quantitative differences were apparent.