Insulin-like growth factor I and its binding protein-3 are regulators of lactation and maternal responsiveness

Insulin-like growth factor I and its binding protein-3 are regulators of lactation and maternal responsiveness

Blog Article

Abstract Adaptation to motherhood includes maternal behaviour and lactation during the postpartum period.The bondage_leather major organizing centres of maternal behaviour and lactation are located in the hypothalamic medial preoptic area (MPOA) and the arcuate nucleus, respectively.Insulin-like growth factor I (IGF-I) is an effector of the growth hormone axis; however, its function in the brain is largely unexplored.We identified increased maternal IGF binding protein-3 (IGFBP-3) expression in preoptic rat microarray data and confirmed it by RT-PCR.

In situ hybridization histochemistry showed markedly elevated IGFBP-3 expression in the MPOA and the arcuate nucleus in rat dams.Prolonged intracerebroventricular injection of IGF-I or antagonism of brain IGFBP-3 with an inhibitor (NBI-31772) using osmotic minipumps increased pup retrieval time, suggesting reduced maternal motivation.Suckling-induced prolactin release and pup weight gain were also suppressed by IGF-I, suggesting reduced lactation.In addition, IGF-I-induced tyrosine hydroxylase expression and its specific phosphorylation in tuberoinfundibular dopaminergic neurons suppress prolactin secretion.

Thus, IGF-I may inhibit both behavioural and lactational alterations in mothers.Neurons in the MPOA and arcuate nuclei express IGFBP-3 during the postpartum period to neutralize IGF-I effects.IGFBP-3 can prevent the blockade of maternal behaviour and lactation exerted by IGF-I, suggesting a novel modulatory mechanism underlying the behavioural and hormonal effects Crew Socks during central maternal adaptations.