Abstract
We have previously shown normal levels of lactase activity in the jejunal fluid of preterm infants (1) and have now measured the change in transmucosal potential difference (P.D.) evoked when lactose is infused into the small intestine. The P.D. depends on the absorption of the products of lactose hydrolysis and is therefore a measure of lactase activity. The P.D. generated by 100mM lactose (P.D.L100) was compared to that evoked by 100mM glucose (P.D.G100) giving an index of functional lactase activity. 13 perfusions were performed on 6 infants, gestatlonal age 29 - 36w (mean 31.5w) and birth weight 970 - 2340g (mean 1520g) with a postnatal age of 8 to 57d (mean 28d). The distal duodenum was perfused at 100ml/hr with solutions containing 100mM mannitol, 100nM glucose and 100mM lactose each made isosmolar with 104mM NaCl. Ihe P.D.L100 and P.D.G100 were measured and the ratio P.D.L100 to P.D.G100 calculated.
Results: Mean P.D.L100 was 6.7 ± 0.8mV (mean ± S.E.M.) and P.D.G100 9.9 ± 0.7mV. The ratio of P.D.L100 to P.D.G100 was 0.65 ± 0.04.
Conclusions: Functional lactase activity in these preterm infants is comparable to older infants (2) and adults (3). This method of assessment of lactase activity can be used in the preterm infant to further elucidate postnatal development.
(1) Mayne A.J. et al., Paediatric Research, 18:1049 (1984)
(2) Igarashi Y. et al., Euro. J.Pediatr., 135:255-260(1981)
(3) Read N.W. et al., Gut, 18:640-643 (1977)
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Mayne, A., Durbin, G., Morgan, M. et al. FUNCTIONAL LACTASE ACTIVITY IN PRETERM INFANTS. Pediatr Res 20, 701 (1986). https://doi.org/10.1203/00006450-198607000-00097
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DOI: https://doi.org/10.1203/00006450-198607000-00097