Elevated Plasma Peptide YY in Human Neonates and Infants

Abstract

ABSTRACT. Plasma concentrations of peptide YY ( P W ) were measured in cord blood and at 6, 12, and 18 days of postnatal life in 24 healthy preterm neonates, from cord blood of eight full-term neonates, and from peripheral blood of 13 infants 9 months old. Concentrations were high in cord blood (73 f 9 pmol/liter versus adult fasting 10.4 f 1.3, p < 0.001) and rose postnatally in the premature infants to 399 f 48 pmol/liter at 6 days, 489 f 42 at 12 days, and fell to 414 f 43 at 18 days. Plasma PYY concentrations were much lower in infants 9 months old (32 f 3 pmol/liter), suggesting that the postnatal surge of plasma PYY is a feature of early adaptation to extrauterine life. Gel permeation chromatograms revealed that the major circulating form of PYY in the neonate eluted in a position identical to that of the pure 36 amino acid peptide. There was, however, evidence of two larger molecular forms that may be precursor molecules. Because P W is a peptide that exhibits potent effects on gastrointestinal secretion and motility in humans, these observations suggest that this candidate gut hormone may be important in the adaptation to enteral nutrition in the neonate. (Pediatr Res 20: 1225-1227 Abbreviation PYY, peptide tyrosine tyrosine or peptide W PYY is a recently discovered candidate gut hormone that has a broad spectrum of biological actions (1-5). PYY is produced by endocrine cells in the distal bowel, and plasma concentrations rise in response to the ingestion of food (3, 6, 7). Infusion studies in adult humans, at doses producing increments of plasma PYY concentrations within the physiological range, have revealed potent inhibitory effects on gastric secretion and emptying and also a delay of mouth-cecum transit (8,9). Recently we observed that circulating PYY concentrations in young healthy pigs were greater than those of adult humans and rats (6, 10). Although this difference may have been due to species it raised the possibility that PYY plays a particular role in the developing animal (7). The aim of the present study was to measure plasma PYY concentrations at birth and in early life to evaluate whether this peptide could be important in the adaptation of the human neonate to extrauterine life. PATIENTS AND METHODSHealthy infants born before 34 wk gestation entered the study, which was approved by the hospital ethics committee. Informed parental consent was also obtained; 24 infants were studied. The mothers of 15 of these (birth weight 1620 _+ 67 g, gestation 32 _+ 1 wk, mean _+ SE) wanted to establish lactation, and their infants were fed only with regular boluses of breast milk by nasogastric feeding tube. The nine infants of mothers not wishing to breastfeed (birth weight 1564 _+ 1 17 g, gestation 3 1 _+ 1 wk, mean _+ SE) were given regular boluses of an adapted milk formula (Nenatal, Nutricia International BV) in daily volumes as recommended by the manufacturer. Both groups of infants tolerated their feeds well and gained weight as expected. None developed diarrhea or any other complication, and ...

Peptide YY (3-36) Represents a High Percentage of Total PYY Immunoreactivity in Preterm and Full-Term Infants and Correlates Independently With Markers of Adiposity and Serum Ghrelin Concentrations

“…We found that PYY (3-36) accounted for a high percentage (almost 50%) of total PYY immunoreactivity in our study population, similarly to previous reports in adults (1), and in accordance with the demonstration of both isoforms of PYY, in equal amounts, in fetal intestinal tissues (17). However, it contradicts the results of the study of Adrian et al showing that, on gel permeation chromatography, the majority of circulating PYY-like immunoreactivity, in the neonate, eluted in an identical position to the pure 36 amino acid PYY standard; thus represented the PYY (1-36) (18). As that method was not specific in the detection of the PYY (3-36) isoform, the discrepancy between the results of that study and ours is probably due to the different methodology applied.…”

Circulating Peptide YY Concentrations Are Higher in Preterm than Full-Term Infants and Correlate Negatively with Body Weight and Positively with Serum Ghrelin Concentrations

“…To our knowledge, this is the first study in which circulating concentrations of both PYY and ghrelin were measured in preterm infants and the correlations between these hormones and anthropometric measures, food intake, and growth rates were examined. Circulating PYY concentrations have been measured in a limited number of studies involving preterm infants (17)(18)(19), and the concentrations reported were as high as in our study. Berseth et al (19 ) compared PYY concentrations in preterm and full-term infants and reported higher concentrations in preterm infants, although the difference did not reach statistical significance.…”

“…circulating concentrations of PYY were higher at day 12 of life than those observed at day 6 in healthy preterm infants (17 ). Similarly, circulating ghrelin concentrations have been reported to peak after the first postnatal month and up to the 24th month in healthy full-term infants (8 ).…”

“…Thus, predominance of Y1 over Y2 receptors could cause an orexigenic instead of the expected anorexigenic action of PYY . In preterm infants, the majority of circulating PYY-like immunoreactivity has been reported to be of a magnitude similar to that of the PYY (1-36) concentration (17 ), but the distributions of Y1 and Y2 receptors are not known.…”

The effects of oral liquid and intravenous glutamine on bowel adaptation in a rabbit short bowel syndrome model

“…After intestinal resection, glutamine application dramatically increased plasma peptide YY (PYY). It was demonstrated that this increase also leads to increase in tissue PYY content, and thus transit passage time in the intestine shortens and food absorption in the shortened intestines increases (37). It was also shown that PPY functionally damps the discharge of the stomach and extends intestinal passage time after colorectal surgery (38)(39)(40)(41)(42).…”