The relationship between serum levels of prolactin and growth hormone in the early postnatal period

Abstract

BackgroundIn the neonatal period, the pituitary hormones including prolactin (PRL) and human growth hormone (hGH) are secreted in high amounts due to immature feedback mechanisms. As both hormones are secreted in part by the same somatomammotrophic cells, we investigated their relationship in newborns with respect to sex, gestational week, method of delivery, and anthropometric data.MethodsThe serum levels of PRL and hGH were measured in blood drawn from 225 newborns. The newborn data were extracted from medical records.ResultsA positive correlation was found between log-transformations of PRL and hGH (r=0.17; P=0.01; n=225), with a stronger correlation in newborns whose blood samples were taken more than 2 days after birth (r=0.42; P<0.001; n=130). Log-transformations of the PRL/hGH ratio demonstrated a positive correlation with the gestational week (r=0.39; P<0.001; n=200). Multiple regression analysis showed that 15% of the variance in the logarithm of this ratio is attributed to the gestational week.ConclusionIn newborns, serum PRL and hGH levels show a positive correlation that can be explained by common regulatory factors or a drift phenomenon. A higher gestational week is associated with a higher PRL/hGH ratio. Further studies are needed to look for possible confounders and to determine the PRL-hGH relationship in different conditions.

Hormonal Determinants of Growth and Weight Gain in the Human Fetus and Preterm Infant

“…Together with a lack of insulating white adipose stores, these predispose to neonatal hypothermia. The low levels of leptin and high levels of prolactin [ 136 , 323 ], together with a rise acylated ghrelin [ 324 , 325 ] may contribute to weight re-gain and may explain in part the subsequent (relative) adiposity of preterm infants: hypoleptinemia is associated with higher rates of weight gain in infancy [ 326 , 327 , 328 ]. Leptin concentrations in preterm as well as term infants initially fall after delivery owing to the loss of the placenta and the transient lack of nutrient intake.…”

Prolactin and its correlation with gestational age and birth weight in a new-born

“…Prolactin and Growth hormone are both anterior pituitary hormones that are almost identical in structure and is responsible for cell proliferation and growth [1] . Prolactin levels in the fetus gradually increases during pregnancy [2] .…”

“…Prolactin levels in the fetus gradually increases during pregnancy [2] . Prior to birth, human Growth hormone variant and Human Placental Lactogen along with Prolactin and Insulin like growth factor IGF 1 is responsible for the growth and development of the fetus [1] . In normal pregnancy, the rise of maternal prolactin occurs gradually from 10-20 ng/ml (pre pregnancy level) to 200-400 ng/ml at term [3] .…”