Postnatal development of plasma prolactin level in premature infants with and without NaCl supplementation.
The role of prolactin in the adaptation of premature infants to the alterations of sodium balance was investigated by measuring plasma prolactin levels serially in 7 low birth weight, premature infants with (group I) and without (group II) NaCl supplementation. The study was performed on the 7th day and weekly thereafter until the 5th week of life. NaCl supplementation was given in a dose of 3-5 mEq/kg/day and 1.5-2.5 mEq/kg/day for 8-21 days and 22-35 days, respectively. It was demonstrated that before NaCl supplementation plasma prolactin concentration was similarly elevated in the two groups (6,490 +/- 1,291 mU/l in group I versus 7,661 +/- 1,094 mU/l in group II), and without supplementation it remained at about the same level throughout the study. When supplemental sodium was given, the plasma prolactin level declined with age at a steady rate to the mean value of 3,516 +/- 502 mU/l by the end of 5th week. In the 3rd-5th weeks it proved to be significantly higher in group II than in group I. It is concluded that physiological sodium depletion may account for the prolonged hyperprolactinemia and prolactin might have some importance in the control of sodium homeostasis in low birth weight, premature infants.
D000367:Age Factors; D005500:Follow-Up Studies; D005865:Gestational Age; D006801:Humans; D007010:Hyponatremia / Q000097:blood / Q000188:drug therapy; D007223:Infant; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature; D011388:Prolactin / Q000037:antagonists & inhibitors / Q000097:blood*; D012965:Sodium Chloride / Q000008:administration & dosage*
D012965:Sodium Chloride; D011388:Prolactin