Using nonpersistent radicals generated by UV-irradiation of endogenous metabolite precursors for dissolution DNP avoids the need for radical filtration and may potentially lengthen the measurement window of hyperpolarized MRI measurements. Here, the endogenous pyruvate-analogues alpha-ketobutyrate and alpha-ketovalerate were proposed as nonpersistent radical precursors. Radical yields were characterized along with their performance as polarizing agents for in vitro and in vivo dDNP experiments. A 13C-glucose liquid state polarization of 26.4% was attained using alpha-ketobutyrate-derived radical, while pyruvate-derived radical yielded 21.7% (compared to 18.9% reported with the persistent trityl radical). Alpha-ketobutyrate was used to hyperpolarize [1-13C]butyrate and measure cardiac metabolism in vivo.