Identification of hypoxanthine in bovine follicular fluid

Bovine follicular fluid (bFF) blocks the occurrence of spontaneous germinal vesicle breakdown (GVBD) of isolated mouse oocytes. One of the active factors was purified by ultrafiltration through a PM-10 membrane filter, gel filtration through Sephadex G-25, and HPLC using a reversed-phase ODS-3 column and a Superose 12 column. This factor was identified as hypoxanthine by gas chromatography and mass spectrometry. The purified substance and hypoxanthine showed the same retention time on HPLC, and identical UV absorbance and mass spectra. There are other oocyte maturation inhibitors in follicular fluid that should be identified.