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Elevated plasma Met-enkephalin levels in the human newborn are a poor indicator of perinatal stress

  • Author Footnotes
    a From the Department of Pediatrics, King-Drew Medical Center, Los Angeles Medical Center, University of California, Los Angeles School of Medicine.
    Alma M. Martinez
    Correspondence
    Reprint requests: Alma M. Martinez, MD, Harbor-UCLA Medical Center, 1000 W. Carson St., RB#1, Torrance, CA 90509.
    Footnotes
    a From the Department of Pediatrics, King-Drew Medical Center, Los Angeles Medical Center, University of California, Los Angeles School of Medicine.
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  • Author Footnotes
    b the Department of Pediatrics, Harbor-University of California, Los Angeles Medical Center, University of California, Los Angeles School of Medicine.
    James F. Padbury
    Footnotes
    b the Department of Pediatrics, Harbor-University of California, Los Angeles Medical Center, University of California, Los Angeles School of Medicine.
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  • Author Footnotes
    b the Department of Pediatrics, Harbor-University of California, Los Angeles Medical Center, University of California, Los Angeles School of Medicine.
    Leslie M. Barberie
    Footnotes
    b the Department of Pediatrics, Harbor-University of California, Los Angeles Medical Center, University of California, Los Angeles School of Medicine.
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  • Author Footnotes
    b the Department of Pediatrics, Harbor-University of California, Los Angeles Medical Center, University of California, Los Angeles School of Medicine.
    Elizabeth E. Burnell
    Footnotes
    b the Department of Pediatrics, Harbor-University of California, Los Angeles Medical Center, University of California, Los Angeles School of Medicine.
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  • Author Footnotes
    b the Department of Pediatrics, Harbor-University of California, Los Angeles Medical Center, University of California, Los Angeles School of Medicine.
    Siang Thio
    Footnotes
    b the Department of Pediatrics, Harbor-University of California, Los Angeles Medical Center, University of California, Los Angeles School of Medicine.
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  • Author Footnotes
    a From the Department of Pediatrics, King-Drew Medical Center, Los Angeles Medical Center, University of California, Los Angeles School of Medicine.
    b the Department of Pediatrics, Harbor-University of California, Los Angeles Medical Center, University of California, Los Angeles School of Medicine.
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      Objective: This study was designed to investigate whether plasma Met-enkephalin peptides could serve as markers of physiologic stress in the neonate.
      Study Design: Infants (n = 115) between 1.2 and 4.7 kg and 28 and 42 weeks of gestation were studied at birth. Seventy-four infants were delivered by the vaginal route, 31 by cesarean section after labor, and 10 by cesarean section before labor. Correlations were sought between plasma enkephalin peptides and epinephrine, norepinephrine, and arterial blood gases with linear regression analysis. Various clinical data were also analyzed.
      Results: Plasma Met-enkephalin levels were significantly greater in infants exposed to labor (440 ± 36 vs 260 ± 30 pg/ml, p < 0.05). The large-molecular-weight forms of enkephalin peptides were also greater in these infants (approximately 50 ± 4 vs 23 ± 2 ng/ml). There was no correlation between plasma enkephalin peptides and catecholamines, arterial pH, or Apgar scores. There was a significant but weak correlation between plasma Met-enkephalin levels and birth weight (r = 0.34, p = 0.03) and Pao2 (r = −0.28, p < 0.05).
      Conclusion: The lack of correlation between Met-enkephalin plasma levels and umbilical plasma catecholamine concentrations, acid-base status, or Apgar scores suggests that circulating Met-enkephalin is a poor indicator of stress in the newborn.

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      References

        • Winkler H
        • Apps DK
        • Fischer-Colbrie R
        The molecular function of adrenal chromaffin granules: established facts and unresolved topics.
        Neuroscience. 1986; 18: 261-290
        • Chaminade M
        • Foutz AS
        • Rossier J
        Co-release of enkephalin and precursors with catecholamines by the perfused cat adrenal in-situ.
        J Physiol. 1984; 353: 157-169
        • Medbak S
        • Mason DFJ
        • Rees LH
        Plasma met-enkephalin and catecholamine responses to insulin-induced hypoglycemia in greyhounds.
        J Endocrinol. 1987; 114: 81-87
        • Martinez AM
        • Padbury JF
        • Burnell EE
        • Thio SL
        • Humme J
        The effects of hypoxia on methionine enkephalin peptide and catecholamine release in fetal sheep.
        Pediatr Res. 1990; 27: 52-55
        • Martinez AM
        • Padbury JF
        • Burnell EE
        • Thio SL
        Plasma methionine enkephalin levels in the human newborn at birth.
        Biol Neonate. 1991; 60: 102-107
        • Langerkrantz H
        • Bistoletti P
        Catecholamine release in the newborn infant at birth.
        Pediatr Res. 1977; 11: 889-893
        • Padbury JF
        • Roberman B
        • Oddie TH
        • et al.
        Fetal catecholamine release in response to labor and delivery.
        Obstet Gynecol. 1982; 60: 607-611
        • Pierzchala K
        • Van Loon GR
        Plasma native and peptidase-derivable met-enkephalin response to restraint stress in rats.
        J Clin Invest. 1990; 85: 861-873
        • Peuler JD
        • Johnson GA
        Simultaneous single isotope radioenzymatic assay of plasma norepinephrine, epinephrine and dopamine.
        Life Sci. 1977; 21: 626-636
        • Holaday JW
        Cardiovascular effects of endogenous opiate systems.
        Annu Rev Pharmacol Toxicol. 1983; 23: 541-594
        • Hughes G
        Naloxone and methylprednisolone sodium succinate enhance sympathomedullary discharge in patients with septic shock.
        Life Sci. 1984; 35: 2319-2326
        • Chernick V
        • Madansky DL
        • Lawson EE
        Naloxone decreases the duration of primary apnea with neonatal asphyxia.
        Pediatr Res. 1980; 14: 357-359
        • Chernick V
        • Craig RG
        Naloxone reverses neonatal depression caused by fetal asphyxia.
        Science. 1982; 216: 1252-1253
        • De Boeck C
        • Van Reempts P
        • Rigatto H
        • et al.
        Naloxone reduces the decrease in ventilation induced by hypoxia in newborn infants.
        J Appl Physiol. 1984; 56: 1507-1511
        • Wardlaw SL
        • Stark RI
        • Daniel S
        • et al.
        Effects of hypoxia on ß-endorphin and ß-lipotropin release in fetal, newborn and maternal sheep.
        Endocrinology. 1981; 108: 1710-1715
        • Wardlaw SL
        • Stark RI
        • Baxi L
        • et al.
        Plasma ß-endorphin and ß-lipotropin in the human fetus at delivery: correlation with arterial pH and PO2.
        J Clin Endocrinol Metab. 1979; 49: 888-891
        • Davidson S
        • Gil-Ad I
        • Rogovin H
        • et al.
        Cardiorespiratory depression and plasma ß-endorphin levels in low-birth weight infants during the first day of life.
        Am J Dis Child. 1987; 141: 145-148
        • Konishi S
        • Tsunoo A
        • Otsuka M
        Enkephalins presynaptically inhibit cholinergic transmission in svmpathitic ganglia.
        Nature. 1979; 282: 515-516
        • Kumakura K
        • Karoum F
        • Costa E
        Modulation of nicotinic receptors by opiate receptor agonists in cultured adrenal chromaffin cells.
        Nature. 1980; 83: 489-492
        • Schadt JC
        • Gaddis RR
        Endogenous opiate peptides may limit norepinephrine release during hemorrhage.
        J Pharmacol Exp Ther. 1985; 232: 656-660
        • Martinez AM
        • Padbury JF
        • Shames L
        • Evans C
        • Humme J
        Naloxone potentiates epinephrine release during hypoxia in fetal sheep: dose response and cardiovascular effects.
        Pediatr Res. 1988; 23: 343-347
        • Padbury JF
        • Agata Y
        • Polk D
        • Wang D
        • Callegari C
        Neonatal adaptation: naloxone increases the catecholamine surge at birth.
        Pediatr Res. 1987; 21: 590-593
        • Schultzberg M
        • Hokfelt T
        • Lundberg JM
        • et al.
        Enkephalin-like immunoreactivity in nerve terminals in sympathetic ganglia and adrenal medulla and in adrenal medullary gland cells.
        Acta Physiol Scand. 1978; 103: 475-477
        • Viveros OH
        • Diliberto EJ
        • Hazum E
        • Chang K
        Opiatelike materials in the adrenal medulla: evidence for storage and secretion with catecholamines.
        Mol Pharmacol. 1979; 16: 1101-1108
        • La Gamma EF
        • Itskovitz J
        • Rudolph AM
        Maturation of circulatory responses to methionine enkephalin.
        Pediatr Res. 1983; 17: 162-167
        • Lewis AB
        • Ferry DA
        • Sadeghi M
        Fetal cardiovascular and breathing movement responses to endogenous opiates.
        Biol Neonate. 1986; 50: 278-287