Effect of transamniotic administration of epidermal growth factor on fetal rabbit small intestinal nutrient transport and disaccharidase development

As fetal swallowing is documented in utero, supplementation of the ingested amniotic fluid with nutrients or hormones has been postulated as a potential prenatal treatment for intrauterine growth retardation (IUGR). To study the effect of epidermal growth factor (EGF) on the developing fetal small intestine, 12 pregnant rabbits underwent operation on day 24 of a normal 31-day gestation. Bilateral ovarian end fetuses underwent catheterization of their respective amniotic cavities with attachment to a miniosmotic pump. study fetuses received recombinant human EGF at ∼300 μg/kg/d for 1 week; controls received carrier solution only at an equivalent rate. On gestational day 31, fetuses were delivered by cesarean section and somatic measurements were recorded. The small intestine was harvested and proximal, middle, and distal regions were analyzed for lactase and maltase enzyme activity. Additionally, the uptake of radiolabeled glucose and proline was measured by a standard everted mucosal sleeve technique for each segment. Results were analyzed by Student's paired t test and reported as mean±SEM. Nine fetal pairs survived (75%). Small intestinal (SI) length was increased in EGF fetuses (54.8±1.9 cm) versus control (50.4±2.7 cm) (P=.02). Lactase activity, reported as UE/g protein, was significantly increased in the proximal segments in the EGF-infused fetuses; maltase was significantly increased in both the proximal and middle segments (P<.05). Nutrient transport of both glucose and proline demonstrated a trend to increase in all segments when analyzed per cm and per mg tissue, reaching significance in the proximal regions for both substrates (P<.05). This report provides the first description of the in situ effects of supplemental EGF administration on fetal rabbit small intestinal development. The inclusion of EGF in supplemental amniotic feeding solutions is supported.