title: Maternal dietary substrates and human fetal biophysical activity. I. The effects of tryptophan and glucose on fetal breathing movements.
abstract: To study the effects of L-tryptophan and glucose on fetal breathing activity, we examined 40 women with normal term pregnancies, randomly assigned to four equal groups who either continued fasting (group C), received 1 gm of oral tryptophan (group T), received 100 gm of oral glucose (group G), or received both substrates (group T + G). Studies lasted 210 minutes, during which fetal breathing movements were observed with real-time ultrasonography and entered and analyzed for incidence, rate, and variability on a microcomputer. Plasma glucose and tryptophan levels were determined every 30 minutes. The incidence of fetal breathing movements declined in group C and rose significantly in the other groups. Breathing rates were unchanged in groups C and T but rose significantly in groups G and T + G during peak breathing intervals. Breath interval variability did not change significantly in any study group. Maternal administration of tryptophan is associated with an alteration in fetal breathing activity but to a lesser degree than that observed after maternal glucose loading.
mesh_terms: D000284:Administration, Oral; D004032:Diet; D005215:Fasting; D005260:Female; D005333:Fetus / Q000187:drug effects / Q000502:physiology*; D005947:Glucose / Q000008:administration & dosage* / Q000494:pharmacology; D006801:Humans; D011247:Pregnancy; D012119:Respiration / Q000187:drug effects*; D014364:Tryptophan / Q000008:administration & dosage* / Q000097:blood / Q000494:pharmacology
chemical_list: D014364:Tryptophan; D005947:Glucose