[Plasma prolactin response to suckling stimulation in puerperal women].
Plasma PRL response to suckling was studied during the 1st week, between the 1st and 2nd weeks and between the 4th and 5th weeks postpartum. During the 1st week, mean (+/-SE) basal PRL significantly rose from 201.9 +/- 27.5 ng/ml to 294.7 +/- 25.6 ng/ml at 15 min and 300.9 +/- 25.9 ng/ml at 30 min after suckling had begun. Between the 1st and 2nd weeks, mean basal levels and the responses to suckling were not significantly different from those during the 1st week. Between the 4th and 5th weeks, mean basal values were considerably lower and the responses to suckling were significantly greater [51.8 +/- 6.9 ng/ml at 0 min; 212.9 +/- 14.8 ng/ml at 15 min and 239.3 +/- 21.4 ng/ml at 30 min] than those within the 2nd week. Assessment of intersubject variations within the 5th week revealed that a significant inverse correlation existed between the basal levels and the suckling-induced maximum increments in PRL (r = -0.538, p less than 0.001). The effects of the oral administration of two serotonin antagonist (cyproheptadine and metergoline) and the dopamine infusion on plasma PRL levels and the response to suckling were investigated during the 1st week postpartum. Metergoline and dopamine suppressed basal PRL levels and abolished the response to suckling, whereas cyproheptadine suppressed the response less effectively without modifying the basal levels. These data suggest that in the early puerperal period an inverse relationship exists between the basal level and the response to suckling in plasma PRL. The suckling-induced PRL release may be mediated via a serotonergic as well as a dopaminergic pathway.
D003533:Cyproheptadine / Q000494:pharmacology; D004298:Dopamine / Q000494:pharmacology; D005260:Female; D006801:Humans; D007774:Lactation; D008711:Metergoline / Q000494:pharmacology; D049590:Postpartum Period; D011247:Pregnancy; D011388:Prolactin / Q000097:blood*; D013391:Sucking Behavior / Q000502:physiology
D008711:Metergoline; D003533:Cyproheptadine; D011388:Prolactin; D004298:Dopamine