Partial purification of a luteotrophic substance from bovine fetal cotyledon granules.
To determine whether luteotrophic activity is present in the bovine placental granules, fetal cotyledons from fetuses of 50-100 days of gestation were used. Enriched granules were prepared using a Percoll gradient. Active substances were obtained from the granules by freeze-thawing. The extracts thus obtained were then eluted on a Sephacryl S-300 column. The resultant fractions were then analysed by (1) a radioreceptor assay for hCG-like substances and (2) a bioassay using progesterone production by bovine luteal cells. There were two peaks of activity, one indicative of a high molecular weight substance and the second of a low molecular weight substance. Higher molecular weight substances were eliminated by using acidic extracts. The low molecular weight fraction was further analysed using reverse phase h.p.l.c. (acetonitrile:water gradient). The elution of this substance at 45% acetonitrile resulted in a 100-fold increase in luteotrophic activity in the bioassay compared to the Sephacryl fraction. The small molecular weight substance is heat-stable and not extracted to the organic phase when partitioned between methanol and chloroform.
Izhar
M
M
Department of Hormone Research, Kimron Veterinary Institute, Bet Dagan, Israel.
Shemesh
M
M
D000818:Animals; D002417:Cattle; D002850:Chromatography, Gel; D003340:Corpus Luteum Maintenance; D004586:Electrophoresis; D005260:Female; D005333:Fetus / Q000032:analysis*; D006065:Gonadotropins, Pituitary / Q000302:isolation & purification*; D015336:Molecular Probe Techniques; D009479:Neuropeptides / Q000302:isolation & purification*; D011247:Pregnancy
D006065:Gonadotropins, Pituitary; D009479:Neuropeptides