Ingestion of excessive preformed vitamin A by mothers amplifies storage of retinyl esters in early fetal livers of captive Old World monkeys

Abstract

Excessive preformed vitamin A (VA) intake is contraindicated during pregnancy because of teratogenic concerns. Recent studies have provided biochemical and histologic evidence of chronic hypervitaminosis A in captive Old World monkeys consuming laboratory diets containing high concentrations of retinyl acetate. To investigate the effects of maternal chronic overconsumption of preformed VA on VA storage in early fetal liver, we analyzed monkey fetal livers ranging from 35 to 93 d gestational age (comparable with mid-first to late second trimester in humans) for VA (n = 19) and retinoic acid (n = 9). Retinyl esters were identified in all fetal livers, and retinol, on a percentage basis, was more abundant in younger fetuses. Liver VA concentration increased with gestational age, ranging from 0.0011 to 0.26 micromol/g in the youngest (35 d) and oldest fetuses (93 d), respectively. Liver VA concentrations (mean +/- 1 standard deviation) were 0.023 +/- 0.008 micromol/g in early gestation and 0.19 +/- 0.06 micromol/g in midgestation fetuses. All-trans retinoic acid concentrations were higher in early gestation (99.2 +/- 57.0 pmol/g, n = 6) than in midgestation (18.2 +/- 6.1 pmol/g, n = 3) but were variable. Liver VA concentrations from midgestation fetuses were higher than those in fetal human and monkey livers from later stages of development, when growth and VA accumulation rates are assumed to be highest. Therefore, excessive intake of preformed VA by the mothers results in amplified early fetal liver retinyl ester storage.