Identification and measurement of 4-oestren-3,17-dione (19-norandrostenedione) in porcine ovarian follicular fluid using high performance liquid chromatography and capillary gas chromatography-mass spectrometry.

4-Oestren-3,17-dione (19-norandrostenedione) has been identified as a major steroid in porcine ovarian follicular fluid for the first time. This steroid was isolated by C18 reverse-phase high performance liquid chromatography (HPLC) and its structure was established unambiguously by capillary gas chromatography-mass spectrometry. The mean concentration in pooled fluid obtained from prepubertal gilts determined by HPLC and capillary gas chromatography was 1.71 mumol/l. The leve of this steroid in fluid obtained from large preovulatory follicles of sows exceeded 21.0 mumol/l on days 19 and 20 of the oestrous cycle. The high levels of this steroid within the follicle during the follicular phase might imply a possible biological role in follicular development and oocyte maturation.