Effect of taurine deficiency on tissue taurine concentrations and pregnancy outcome in the rat

Taurine status and pregnancy outcome were assessed in rats fed low dietary taurine and varying doses of guanidinoethyl sulfonate (GES), a structural analogue of taurine. Female Sprague–Dawley rats (225–270 g) were mated overnight and assigned to one of four groups from day 0 to 20 of gestation. Taurine-deficient animals were fed a basal diet containing <0.001 μmol taurine/g and 0.5 (n = 7), 1.0 (n = 8), or 2.0% (n = 7) GES in their drinking water, ad libitum. Control animals (n = 8) received similar treatment, with 2 μmol taurine/g added to the diet and no GES in their water. Taurine was analyzed by reverse-phase HPLC, using electrochemical detection after precolumn derivatization with ortho-phthalaldehyde. Treatment of rats with varying doses of GES produced a sharp decline in maternal liver and brain taurine to 15 and 55% of that of control levels, and in fetal liver and brain taurine to 75 and 50% of that of control levels, respectively (p = 0.0001; one-way ANOVA). The 2% group had a smaller mean (±SEM) litter weight than the control group (35.8 ± 6.1 vs. 51.9 ± 2.8 g; p = 0.042) as a result of a smaller litter size. The decrease in litter size was associated with confinement of implantation sites to either the left or right uterine horn in four of seven dams. Taurine deficiency did not result in intrauterine growth retardation or significant external, visceral, or skeletal malformations. Developmental defects were not found in any of the taurine-deficient groups, but reproductive abnormalities were present at the highest dose of the analogue.Key words: taurine deficiency, guanidinoethyl sulfonate, pregnancy outcome, congenital malformations, unilateral pregnancy.