title: Development of a circadian variation of plasma oxytocin concentration in the late gestation rhesus monkey.
abstract: The 24-h pattern of oxytocin (OT) concentrations in maternal plasma was investigated serially from 112-168 days gestation in four chair-restrained pregnant rhesus monkeys. No change in the mean daily plasma OT concentration was observed with advancing gestational age; there was a change in the pattern of plasma OT secretion throughout the period, however. About 21 days from delivery (150.8 +/- 1.8 days gestational age), plasma OT levels showed occasional fluctuations, distributed throughout the day. About 8 days from delivery (163.2 +/- 2.4 days gestational age), a clear circadian pattern of OT was detected, with an acrophase at 2200 h. These results suggest that there is a relationship between the pattern of OT secretion and advancing pregnancy. This may account partially for the increase in uterine activity known to occur in term rhesus monkeys.
authors.affiliation: Department of Obstetrics, Gynecology, and Reproductive Sciences, University of California, San Francisco 94143.
authors.forename: M
authors.initials: M
authors.lastname: Seron-Ferre
authors.forename: N F
authors.initials: NF
authors.lastname: Taylor
authors.forename: M C
authors.initials: MC
authors.lastname: Martin
authors.forename: R D
authors.initials: RD
authors.lastname: Leake
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D005260:Female; D005865:Gestational Age; D008253:Macaca mulatta; D009994:Osmolar Concentration; D010121:Oxytocin / Q000097:blood*; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000097:blood*
chemical_list: D010121:Oxytocin