Dynamic Evaluation of Prolactin Secretion during the Early Hours of Life in Human Newborns

Abstract

PRL [prolactin] secretion was evaluated in 30 human newborns during the early hours of life. Both L-dopa and pyridoxine administration failed to suppress PRL release in all subjects. Synthetic TRH [thyrotropin releasing hormone] elicited a constant, prompt increase in PRL levels. No significant changes were observed after somatostatin injections. These results demonstrate normal pituitary PRL reserve in newborns. The failure to respond to L-dopa and pyridoxine administration might reflect partial immaturity of the pituitary dopaminergic receptors.