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Plasma β-Casomorphin-7 Immunoreactive Peptide Increases after Milk Intake in Newborn but not in Adult Dogs

Pediatric Research volume 26, pages 3438 (1989) | Download Citation



ABSTRACT: To determine the relation between milk intake and plasma levels of β-casomorphins as a function of age, we studied the levels of β-casomorphin-7 immunoreactive material (BCMIR) in 2- and 4-wk-old beagle neonates and adult dogs following milk intake. We used three kinds of milk: 1) bovine casein-based milk formula; 2) canine bitch's milk, and 3) soy protein-based (noncasein) formula. Using a new extraction technique, BCMIR was isolated from plasma and assayed by radioimmunoassay at 0, 2, 4, and 6 h after feeding. We found that BCMIR increased significantly in both 2- and 4-wk-old puppies post bovine and canine milk feeding, but not after soy protein formula. Base-line values were about 80-120 fmol/ml and increased to 100-120% 2 h after bovine casein intake in the older puppies and by 4 h in the younger group. BCMIR levels were undetectable in adult dogs before or after bovine milk feeding. β-casomorphin-7 added to plasma was rapidly degraded whereas BCMIR was stable. Chromatographic profiles demonstrated that the BCMIR moiety is larger than β-casomorphin-7. Our data suggest that the appearance of BCMIR in the plasma of neonatal dogs is a result of β-casein degradation along a permeable gastrointestinal mucosa. We speculate that morphiceptin and β-casomorphins can be cleaved from BCMIR and may have important physiologic effects.

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  1. Department of Pediatrics (Pulmonary Division), Columbia University College of Physicians and Surgeons, New York, New York 10032; and Division of Cell Biology, Burroughs Wellcome Co., Research Triangle Park, North Carolina 27709

    • Malathy Singh
    • , Carol L Rosen
    • , Kwen Jen Chang
    •  & Gabriel G Haddad


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Correspondence to Gabriel G Haddad.

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