Abstract
BackgroundThe molecular components determining the timing for birth remain an incompletely characterized aspect of reproduction, with important conceptual and therapeutic ramifications for management of preterm, post-term and arrested labor.Methodology/Principal FindingsTo test the hypothesis that oxytocin mediates circadian regulation of birth, we evaluated parturition timing following shifts in light cycles in oxytocin (OT)-deficient mice. We find that, in contrast to wild type mice that do not shift the timing of birth following a 6-h advance or delay in the light cycle, OT-deficient mice delivered at random times of day. Moreover, shifts in the light-dark cycle of gravid wild type mice have little impact on the pattern of circadian oxytocin release.Conclusions/SignificanceOur results demonstrate oxytocin plays a critical role in minimizing labor disruption due to circadian clock resetting.
Highlights
The clock metering the duration of pregnancy has been suggested to consist of two interacting timers; an interval timer measuring the overall length of gestation, and a circadian timer defining when within a 24-hour cycle birth takes place [1]
In the absence of a shift, labor timing in oxytocin knockout (OT KO) mice is indistinguishable from that in wild type (WT) mice, either shift causes the OT KO mice to lose the circadian distribution of labor
This oxytocin rhythm does not shift with changes in the light cycle during gestation indicating that it is controlled by a circadian pacemaker distinct from the master clock that regulates locomotor activity
Summary
The clock metering the duration of pregnancy has been suggested to consist of two interacting timers; an interval timer measuring the overall length of gestation, and a circadian timer defining when within a 24-hour cycle birth takes place [1]. It was surprising that oxytocin-deficient mice had no abnormalities in the overall duration or progression of labor [5,6] These studies suggest that oxytocin does not play an indispensable role in the interval timer of birth. Given the strong evolutionary conservation of oxytocin regulation during pregnancy, and its known circadian release in virgin and gravid animals [7,8], we hypothesized that oxytocin instead mediates circadian gating of birth. To test this hypothesis, we evaluated the effects shifts in a 12-h light-12-h dark cycle on the timing of parturition in oxytocin-deficient mice. Our results demonstrate oxytocin plays a critical role in minimizing labor disruption due to circadian clock resetting
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
