Preparation of radioactive gibberellin a(1) and its metabolism in dwarf peas

Gibberellin A₁-3,4-³H was prepared by selective catalytic reduction of gibberellic acid with a mixture of tritium and hydrogen. ³H-GA₁ was applied at physiological concentrations to dwarf peas and the metabolism of the hormone was investigated. ³H-GA₁ was converted to an acidic, biologically active compound. Radioactive but biologically inactive compounds were also found in the neutral fraction and could not be converted to acidic gibberellins by hydrolysis. No attachment of gibberellin to any macromolecular fraction was evident.