The nutritional regulation of circulating placental lactogen in fetal sheep.
Maternal and fetal plasma ovine placental lactogen (oPL), insulin, and IGF-I levels were measured in response to the starvation and refeeding of pregnant sheep on two defined planes of nutrition. Chronically catheterized pregnant ewes were placed on either a high plane (n = 5) or low plane (n = 5) of nutrition at least 1 wk before the experiment. At 125 to 135 d gestation, the ewes were starved for 72 h and then an i.v. infusion of 10% glucose was administered over 4 h, followed by refeeding at the designated nutritional plane. Plasma oPL levels of fetuses whose mothers had been on a high plane of nutrition were significantly higher during starvation (p less than 0.05) than those of fetuses whose mothers had been on a low plane (high + 0.54 +/- 0.17 and low -0.02 +/- 0.17 nmol/L from mean control levels). Intravenous glucose infusion to the ewes at the end of starvation caused a marked rise in fetal plasma oPL levels in both groups (increments of 2.61 +/- 1.4 nmol/L in the high group and 2.81 +/- 1.16 nmol/L in the low group). Maternal oPL levels did not differ significantly between the two nutritional groups during starvation and did not change during glucose infusion. Fetal and maternal plasma IGF-I levels both fell during starvation. Maternal IGF-I levels fell faster in the high group (-17.9 +/- 4.5 at 24 h versus -4.7 +/- 7.2 nmol/L in the low group), but the groups were not different at the end of starvation.(ABSTRACT TRUNCATED AT 250 WORDS)
Oliver
M H
MH
Department of Paediatrics, University of Auckland, New Zealand.
Harding
J E
JE
Breier
B H
BH
Evans
P C
PC
Gluckman
P D
PD
D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D007328:Insulin / Q000097:blood; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008431:Maternal-Fetal Exchange; D009752:Nutritional Status; D010928:Placental Lactogen / Q000097:blood*; D011247:Pregnancy; D012756:Sheep; D013217:Starvation / Q000097:blood
D007328:Insulin; D007334:Insulin-Like Growth Factor I; D010928:Placental Lactogen