Effects of streptozotocin-induced diabetes in pregnant rats on placental transport and tissue uptake of alpha-amino-isobutyric acid.
Placental transport and tissue uptake of amino acids were studied in streptozotocin (STZ)-induced diabetic rats by using the non-metabolizable amino acid [U-14C]-alpha-amino-isobutyric acid (AIB). Fifteen minutes prior to autopsy, animals of each group, control (C), diabetic (D), diabetic-insulin treated (DI) and diabetic-T4 followed by 3-5-Dimethyl-3'-isopropyl-L-thyronine (DIMIT) treated (DTD), received an injection of the [U-14C]-AIB SC. Disintegrations per minute (DPM) were measured in serum and tissues subsequent to autopsy. There were no differences in maternal serum DPM/ml among groups. Fetal serum DPM, however, were lower in D and DTD groups than in the C group. The whole fetal tissue homogenate radioactivity was lower in the D, DTD, and DI groups than in the C group. In general, more AIB was taken up by fetal tissues of C than D animals. Maternal liver AIB uptake was reduced in D, DI, and DTD from C animals and net placental transport of AIB was less in D and DTD than C animals. Fetal liver protein concentrations were depressed in D and DTD animals from C and DI, but fetal brain protein concentrations showed no significant differences. Furthermore, the lower organ and fetal body weights of the D and DTD groups compared with the C and DI groups support the proposal that fetal anabolism is impaired. Maternal and fetal serum T4 concentrations were lower in D and DTD than in C and DI animals. Insulin therapy improved serum T4 levels in both mother and fetuses. It did not, however, correct all other measured parameters.(ABSTRACT TRUNCATED AT 250 WORDS)
D000621:Aminoisobutyric Acids / Q000378:metabolism*; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism*; D005260:Female; D005312:Fetal Blood / Q000032:analysis; D005326:Fetal Proteins / Q000378:metabolism; D008431:Maternal-Fetal Exchange; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution
D000621:Aminoisobutyric Acids; D001786:Blood Glucose; D005326:Fetal Proteins; C100049:2-aminoisobutyric acid