Relaxin Inhibits the Pulsatile Release of Oxytocin: DISCUSSION(3)

Exogenous relaxin suppressed the occurrence of reflex milk ejection in the current study, which is in common with other reports. Moreover, there were no pulsatile elevations in circulating oxytocin after relaxin treatment. These findings give credence to the hypothesis that relaxin suppresses oxytocin release stimulated by suckling. It is important to note that relaxin treatment…

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Relaxin Inhibits the Pulsatile Release of Oxytocin: DISCUSSION(2)

In the current study, the onset of sucking by the young rats was associated with a gradual rise in basal circulating levels of oxytocin. It is unlikely that the sampling technique used caused the release of hormone, as preliminary experiments established that 12-15 samples (total volume 2-2.5 ml) did not evoke the release of oxytocin…

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Relaxin Inhibits the Pulsatile Release of Oxytocin: DISCUSSION(1)

We set out to clarify the effects of exogenous relaxin on oxytocin release in suckled and unsuckled rats. Our results show that relaxin induces a small rise in circulating oxytocin in unsuckled, lactating rats, and increases baseline oxytocin in suckled animals between successive milk ejections. This is similar to previous reports. We have also shown…

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Relaxin Inhibits the Pulsatile Release of Oxytocin: RESULTS(3)

Plasma oxytocin concentrations at the start of the sampling period were in the range 35-40 pM. An increase in oxytocin concentrations was observed in the samples collected 5 or 10 sec before the rise in intramammary pressure was detected. Peak concentrations of hormone (392.4 ┬▒ 122.1 pM) were coincident with, or slightly preceded, the onset…

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Relaxin Inhibits the Pulsatile Release of Oxytocin: RESULTS(2)

Experiment 2. Effects of Intravenous Relaxin on the Pulsatile Release of Oxytocin during Reflex Milk Ejection Detailed oxytocin profiles were determined in twenty-one rats showing regular milk ejection in response to the┬ásucking action of the young. The rise in intramammary pressure, indicative of milk ejection, occurred in the middle of the sampling period for seven…

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Relaxin Inhibits the Pulsatile Release of Oxytocin: RESULTS(1)

Experiment 1. Effects of Intravenous Relaxin on Plasma Oxytocin in Lactating Rats Baseline plasma oxytocin concentrations were measured in three groups of lactating rats: before suckling (group 1), after the onset of suckling but before reflex milk ejection started (group 2), and after reflex milk ejection was established (group 3). Plasma oxytocin concentrations were 27.6…

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