Plasma Amino Acids and Glucose Levels in the Rat Fetus and Dam after Chronic Maternal Alcohol Consumption

Abstract

To evaluate the effect of chronic maternal alcohol consumption on plasma amino acid and glucose levels in both the fetus and the mother, female Sprague-Dawley rats were divided into 3 dietary treatment groups. Group 1 (alcohol) was fed ad libitum a stock diet plus 20% alcohol in drinking water for at least 4 weeks before mating and 30% alcohol during gestation. Group 2 was pair-fed the stock diet plus corn starch calorically equivalent to the amount of alcohol consumed by group 1 animals. Group 3 (control) received the stock diet and water ad libitum. On day 21 of gestation the fetuses of alcohol-treated dams weighed significantly less than those of the control and pair-fed groups. Fetal plasma glucose levels were significantly lower in the alcohol group when compared to those of the pair-fed and control groups, while the maternal glucose levels were similar in all three treatment groups. Plasma amino acid concentrations showed no corresponding trends in mother and fetus. Only proline was significantly reduced and alpha-amino-n-butyric acid elevated in the alcohol-treated dams when compared to the pair-fed and control rats. In the fetal plasma, only aspartic acid was significantly lower in the alcohol group when compared to the other two groups. A moderate degree of dehydration occurred in the alcohol-treated dams, but plasma albumin was within normal levels. It is concluded that the marked decrease in the concentration of plasma glucose in alcohol-exposed fetuses may be partially responsible for their retarded growth.

Chronic binge ethanol-mediated acidemia reduces availability of glutamine and related amino acids in maternal plasma of pregnant sheep

“…A final acute challenge of ethanol or acidemia following the chronic exposure resulted in a significant reduction of glutamine, arginine, citrulline, asparagine, serine, threonine, tryptophan, methionine, leucine, histidine, tyrosine, valine, and isoleucine, compared with that at baseline, while glutamate was elevated. Glucose, in contrast, was not altered in response to ethanol, a finding that is consistent with previous reports; maternal ethanol consumption reduces fetal, but not maternal plasma glucose levels (Falconer, 1990; Marquis et al, 1984; Richardson et al, 1985). Utilizing a chronic, but not a binge ethanol exposure during the first two trimester-equivalents of human brain growth in rats, Karl and coworkers (Karl et al, 1995) found increased fetal glutamate levels, but glutamine was not altered in the mother or the fetus.…”

“…Utilizing a chronic, but not a binge ethanol exposure during the first two trimester-equivalents of human brain growth in rats, Karl and coworkers (Karl et al, 1995) found increased fetal glutamate levels, but glutamine was not altered in the mother or the fetus. Other rat studies involving a similar exposure paradigm have demonstrated a decrease in maternal plasma proline levels (Marquis et al, 1984), as well as reduced sodium dependent intestinal absorption of methionine (Polache et al, 1996), and taurine (Martin-Algarra et al, 1998). In contrast to these chronic exposure studies, an acute ethanol study in the pregnant mouse resulted in a significant reduction in the plasma concentrations of several amino acids, including threonine, serine, glutamine, glycine, alanine, and methionine (Padmanabhan et al, 2002).…”

“…Acute ethanol exposure in the pregnant mouse results in a significant reduction in the plasma concentrations of threonine, serine, glutamine, glycine, alanine, and methionine (Padmanabhan et al, 2002). Chronic ethanol exposure during the first two trimester-equivalents of human brain growth modeled in the rat has been shown to reduce maternal plasma proline concentration (Marquis et al, 1984). Utilizing a chronic paradigm during the first two trimester-equivalents of human brain growth, Karl and coworkers (Karl et al, 1995) found altered plasma glutamate in the fetal rat, but not in the mother.…”

Acute alcohol exposure, acidemia or glutamine administration impacts amino acid homeostasis in ovine maternal and fetal plasma

“…Maternal plasma concentrations of threonine, serine, glutamine, glycine, alanine, and methionine were reduced in response to acute alcohol exposure in the mouse (Padmanabhan et al 2002) and chronic alcohol exposure in the rat reduced maternal plasma proline concentrations (Marquis et al 1984) and increased fetal plasma glutamate concentrations (Karl et al 1995). These findings characterize the effect of alcohol on maternal amino acids, while there is a paucity of information on the effect to the fetus.…”

Effect of Tryptophan on Livers of Pregnant and Lactating Rats and Their Fetuses and Pups

“…It has been reported that the level of most amino acids is considerably higher in fetal than in maternal blood (14)(15)(16). Tryptophan, as well as total amino acid concentration, in plasma decreases significantly with pregnancy (16) while in the fetus (2 1 days) the plasma tryptophan level is higher (65-91%) than in the mother (16,17). This suggests that the plasma tryptophan level in the fetus may already be high so that an additional elevation via the maternal ingestion of tryptophan may not have a further stimulatory effect.…”