Development of the neonatal rat small intestinal barrier to nonspecific macromolecular absorption. II. Role of dietary corticosterone.
The role of oral corticosterone (C) in the maturation of the neonatal rat jejunal barrier to the absorption of nonspecific macromolecules was evaluated. This was done by adding C to the diet of rat pups weaned at an early age, 17 d, from maternal milk (MM) to either a protein hydrolysate (PH) or soy (S) artificial formula. Both PH and S are known to cause a delay in small intestinal closure to the absorption of a 40-kD glycoprotein tracer, horseradish peroxidase (HRP), on d 21 of age. C was added to PH and S formulas from d 17 to 21 at 0.26 mumol/L (10 micrograms/dL), a level found in the MM of lactating rat dams, or at 10.29 mumol/L (400 micrograms/dL) (PH + 10C, PH + 400C) (S + 10C, S + 400C). Controls consisted of rat pups fed PH or S without C and animals remaining with the dam on MM. The delay in jejunal closure to HRP on d 21 in both PH- and S-fed pups was prevented by C supplementation at both the higher and lower concentrations. Geometric mean (95% confidence intervals) jejunal HRP absorption in PH + 10C pups was 74 (32,167) IU HRP/mL x cm x min, less than in pups fed PH without C [353 (200,615); p less than 0.05] and indistinguishable from HRP absorption in MM-fed animals [111 (79,154)]. HRP absorption in PH + 400C pups [52 (23,115)] was also less than that in animals fed PH without C (p less than 0.01) and indistinguishable from those fed MM.(ABSTRACT TRUNCATED AT 250 WORDS)
Teichberg
S
S
Department of Pediatrics, North Shore University Hospital-Cornell University Medical College, Manhasset, New York 11030.
Wapnir
R A
RA
Moyse
J
J
Lifshitz
F
F
D000818:Animals; D000831:Animals, Newborn; D003345:Corticosterone / Q000008:administration & dosage / Q000494:pharmacology*; D004032:Diet; D006735:Horseradish Peroxidase / Q000493:pharmacokinetics; D007408:Intestinal Absorption / Q000187:drug effects*; D007583:Jejunum / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D008892:Milk; D051381:Rats; D011919:Rats, Inbred Strains; D015430:Weight Gain / Q000187:drug effects
D006735:Horseradish Peroxidase; D003345:Corticosterone