Characterization of ovarian follicular fluids of sheep, pigs and cows using proton nuclear magnetic resonance spectroscopy.

Proton NMR spectra were produced for Graafian follicular fluids obtained by aspiration from sheep, pig and cow ovaries. The following low molecular mass, non-protein-bound metabolites were detected at concentrations exceeding 0.1 mM: acetate, alanine, creatinine/creatine, glycine, D-3-hydroxybutyrate, lactate, valine. Glucose was difficult to quantify and N-acetyl sugars gave a broad resonance at 2.06 ppm, presumably representing side-chains of glycoproteins. Ethanol was detected at up to millimolar concentrations in some specimens, though the physiological significance of this finding was not clear. The concentrations of all metabolites were comparable to those of plasma. These results have therefore shown that NMR spectroscopy is useful for gaining a broad and semiquantitative impression of the more abundant metabolites in the fluids of preovulatory Graafian follicles.