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

Abstract

ABSTRACT. To determine the relation between milk intake and plasma levels of P-casomorphins as a function of age, we studied the levels of P-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 fmoll 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. 0-casomorphin-7 added to plasma was rapidly degraded whereas BCMIR was stable. Chromatographic profiles demonstrated that the BCMIR moiety is larger than ,f3-casomorphin-7. Our data suggest that the appearance of BCMIR in the plasma of neonatal dogs is a result of P-casein degradation along a permeable gastrointestinal mucosa. We speculate that morphiceptin and P-casomorphins can be cleaved from BCMIR and may have important physiologic effects. (Pediatv Res 26: 34-38, 1989) Abbreviations BCMIR, P-casomorphin-7 immunoreactive material TFA, trifluoroacetic acid Recently, peptide fragments of p-casein, a major milk protein, have been shown to possess opioid activity (1). These peptides, known as (3-casomorphins and morphiceptin, exhibit selective popioid receptor activity like that of morphine (2, 3). For example, p-casomorphins have been shown to induce analgesia (4), influence pancreatic function ( 5 , 6), depress cardiorespiratory function (7), and alter behavior (8).Even though the mechanism of cleavage of this peptide from

Hydrolysis of Casein Accelerates Gastrointestinal Transit via Reduction of Opioid Receptor Agonists Released from Casein in Rats

“…Carmine red GIT was signifi cantly higher in rats on hydrolyzed than [16][17][18][19][20] ; p = 0.6). Small bowel transit was also signifi cantly higher with hydrolyzed (78.8 8 7.0%, n = 8) compared to native casein (67.4 8 5.1%, n = 9; p !…”

Bioactive peptides derived from milk proteins. Structural, physiological and analytical aspects

“…The possible physiological importance of opioid substances derived from milk proteins for the neonate [62] may be deduced from the existence of 8-casomorphin immunoreactive material in the plasma of newborn calves after their first bovine milk feeding [25] as well as in two weeks-old dogs after canine milk intake [63]. But casomorphins or precursor molecules of these opioid casein fragments have not been detected in plasma of newborn calves before milk feeding [63] or in adult humas [64].…”

“…But casomorphins or precursor molecules of these opioid casein fragments have not been detected in plasma of newborn calves before milk feeding [63] or in adult humas [64]. Thus, in adult mammals casomorphins cannot enter the cardiovascular compartment, i.e.…”

Autism and gastrointestinal symptoms

“…In vitro research revealed that gluten [20] and casein [21] have potentially opioid segments called gliadorphins [22] and beta-casomorphins [23], respectively. Intact transport of beta-casomorphins has been shown across intestinal The organic acid test is not validated; microbiologic confirmation of the overgrowth is necessary mucosa in the neonatal period in dogs [24]. Altered intestinal permeability has been described in children with autism.…”