Measurement of oxytocin concentrations in plasma and ovarian extracts during the oestrous cycle of mares.
Jugular venous blood samples were collected throughout a complete oestrous cycle from 9 mares for measurement of progesterone and oxytocin by radioimmunoassay. Mean oxytocin concentrations remained at approximately 1 pg/ml throughout, with no evidence of cyclic variation in the release pattern. Extracts of corpus luteum and follicles obtained from a further 33 mares at different stages of the cycle all contained oxytocin concentrations of less than 10 pg/g wet weight of tissue. We conclude that the ovaries are not a source of circulating oxytocin during the oestrous cycle in this species. The plasma oxytocin concentrations reported here are substantially lower than those found by other groups.
Stevenson
K R
KR
Department of Anatomy, School of Medical Sciences, Bristol, UK.
Parkinson
T J
TJ
Wathes
D C
DC
D000818:Animals; D003338:Corpus Luteum / Q000378:metabolism; D004971:Estrus / Q000378:metabolism*; D005260:Female; D006736:Horses / Q000378:metabolism*; D006080:Ovarian Follicle / Q000378:metabolism; D010053:Ovary / Q000378:metabolism*; D010121:Oxytocin / Q000097:blood / Q000378:metabolism*; D011374:Progesterone / Q000097:blood; D011863:Radioimmunoassay / Q000379:methods
D011374:Progesterone; D010121:Oxytocin