Variations in oxytocin, vasopressin and neurophysin concentrations in the bovine ovary during the oestrous cycle and pregnancy

Publisher Website
Google Scholar
Abstract
Bovine ovaries were obtained from the abattoir and corpora lutea were classified as: early luteal phase (.apprx. days 1-4); mid-luteal phase (days 5-10); late luteal phase (days 11-17); regressing (days 18-20) and pregnant (days 90-230). Preovulatory follicles and whole ovaries without luteal tissue were collected. Concentrations of oxytocin, vasopressin, bovine neurophysin I and progesterone were measured in each corpus luteum by radioimmunoassay. Progesterone and neurophysin I levels increased from Stage 1 to Stage 2, plateaued during Stage 3 and declined by Stage 4. Oxytocin and vasopressin concentrations increased from Stage 1 to Stage 2, but declined during Stage 3 and were low (oxytocin) or undetectable (vasopressin) in follicles, whole ovaries and pregnancy corpora lutea. The concentrations of both peptide hormones were maximal during the 1st half of the cycle and declined before those of progesterone. The high concentration of oxytocin within the corpus luteum coupled with the presence of bovine neurophysin I suggests that oxytocin is synthesized locally.

This publication has 17 references indexed in Scilit: