Absorption of methionine by foetal and neonatal lamb colon

Abstract

SummaryProximal colons taken from foetal and newly born lambs have been shown to actively transport methionine from lumen to blood when incubated under in vitroconditions. The lumen to blood flux of methionine, measured across foetal and early post-natal colons was approximately 25 and 15 times greater than the blood to lumen flux, each flux being determined in the presence of 1 mM methionine.The ability of the colon to transport methionine decreased with age, there being no net transport across the colon of a 26-day-old lamb. The post-natal disappearance of this transport function appeared to be roughly exponential with a half-time of approximately 2 days.The short-circuit currents and open-circuit voltages, measured across proximal colons of lambs of different ages, remained stable throughout incubation. The transtissue electrical resistance of colons taken from 9- and 16-day-old lambs was approximately double that recorded across colons taken from younger animals.These results are discussed both in relation to what is already known concerning amino acid transport in the neonatal pig colon and in relation to what their possible physiological significance might be to normal post-natal development in lambs.