FETAL AND PLACENTAL GLUCOSE AND AMINO-ACID-UPTAKE IN THE SPONTANEOUSLY HYPERTENSIVE RAT

Until late in gestation, fetal spontaneously hypertensive rat (SHR) is growth retarded. Fetal growth rate increases after placental hypertro phy occurs between fetal days 18 and 20. The increase in placental mas s may result in improved transfer of macro nutrients to the fetus and thus stimulate growth. In this study, fetal and placental uptake of th e glucose analog 3-O-methyl glucose (3MG) and the amino acid analog am ino-isobutyric acid (AIB) from the maternal circulation were compared in the SHR and Wistar-Kyoto (WKY) on days 16, 20 and 22 of gestation. Placental 3MG uptake (d/min/g tissue met weight) was decreased in the SHR on days 20 and 22 but no differences were observed in fetal 3MG up take. Increased placental mass in the SHR meant that total placental 3 MG uptake was greater in the SHR. Placental uptake of AIB (d/min/g tis sue wet weight) was much lower in the SHR (on days 16, 20 and 22) and the decrease was not compensated for by increased placental mass. Feta l uptake of AIB was decreased on days 20 and 22 (P<0.05). AIB uptake ( d/min/g tissue wet weight) by the carcass and the internal organs (bra in, heart, kidney, liver and lung) was also lower in the SHR. These fi ndings indicate that although fetal growth in the SHR increases rapidl y in late gestation following placental hypertrophy, it does so despit e a pronounced deficit in amino acid uptake. (C) 1998 W. B. Saunders C ompany Ltd. Placenta (1998), 19, 403-408.