Summary
Pregnant rats of 19th and 21st days were given an acute nitrogen overload produced
by an infusion of either 0.2 M ammonium acetate or 0.2 M glutamine. Metabolic adaptations
to nitrogen excess were studied measuring - in fetomaternal unit - non-protein nitrogen
content and the activities of enzymes related with ammonia metabolism. Maternal and
fetal plasma urea levels were increased by ammonium acetate treatment. Glutamine overload
increased more the amino acid content in the mothers than in conceptus. As response
to ammonium acetate treatment, glutamate dehydrogenase activity in liver was more
sensitive in pregnant than in nonpregnant rats, suggesting more nitrogen incorporation
into amino acids in pregnancy. Regarding glutamine synthetase activity, both treatments
had an opposite effect except in kidney. The adenylate deaminase activity of pregnant
rats was inhibited similarly to non-pregnant rats by nitrogen overloads, but stronger
after glutamine infusion. Placenta and fetal metabolism were adjusted, as the dams,
to lack of ammonia production by nitrogen overloads and to glutamine synthesis by
ammonium acetate infusion.
Key words
Rat Gestation - Ammonium Acetate - Glutamine - Amino Acids - Glutamate Dehydrogenase
- Glutamine Synthetase - Adenylate Deaminase
