The presence of EGF- and IGF-1-receptors in the small intestine of fetal, neonatal and weaned piglets

During development, gut morphology and functions change. Some of these are mediated by milk-borne factors, e.g. insulin-like growth factor-1 (IGF-1) and epidermal growth factor (EGF), of which the effects are in part dictated by the distribution of their receptors (R).

EGFR- and IGF-1R-immunoreactivity (IR) was evaluated in samples of the fetal, neonatal and weaned porcine small intestine.

EGFR-IR first appeared in the neonatal duodenum and was located basolaterally in villar and to a lesser extent in cryptal enterocytes. In weaned pigs, EGFR appeared apically in enterocytes with a region-dependent distribution along the villus–crypt axis. IGF-1R-IR was observed in smooth muscle cells in each age group. From the last trimester of gestation onward IGF-1R-IR was seen at the apical and basolateral side of villar enterocytes and in submucosal arterioles.

Thus, the age- and region-dependent presence of EGFR and IGF-1R has to be taken into account when evaluating effects of EGF and IGF-1 on growth or repair.