[The effect of maternal IGF-I on fetal and placental growth in mice].
Insulin-like growth factor-I (IGF-I) is a polypeptide that mediates growth-promoting actions of GH and has insulin-like activity. Increase in the levels of IGF-I in the maternal and fetal circulation during pregnancy and the identification of the specific receptors for IGF-I in a variety of fetal tissues suggest that IGF-I may play a significant role in the regulation of fetal growth. The present study was undertaken to determine the significance of maternal IGF-I on fetal and placental growth by administering the specific antiserum for IGF-I to pregnant mice. The antiserum was produced by repeatedly injecting recombinant IGF-I into rabbits. The antiserum obtained showed 30% binding to 125I-IGF-I at a dilution of 1:240,000, and crossreactivity with IGF-II was 0.012%. In the first set of experiments, pregnant mice were given a daily dose of 50 microliters of the original antiserum (E-1) or normal rabbit serum (C-1) into the peritoneal cavity between Day 3 and 10. In the second set of experiments, antiserum (E-2) or normal rabbit serum (C-2) was administered between Day 11 and 18. On Day 18, all mice were killed, blood was collected for measurement of levels of IGF-I by RIA, and the weights of fetuses and placentas in individual mice were recorded. The maternal levels of IGF-I in group E-1 and E-2 were extremely low compared to those in group C-1 and C-2. The number of fetuses and rate of abortion among each group were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)
Adachi
T
T
Department of Obstetrics and Gynecology, Tokyo Women's Medical College, Japan.
Iwashita
M
M
Watanabe
M
M
Takeda
Y
Y
Sakamoto
S
S
D000818:Animals; D001835:Body Weight; D005314:Embryonic and Fetal Development; D005260:Female; D007106:Immune Sera / Q000494:pharmacology; D007334:Insulin-Like Growth Factor I / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008813:Mice, Inbred ICR; D009929:Organ Size; D010929:Placentation; D011247:Pregnancy; D011817:Rabbits
D007106:Immune Sera; D007334:Insulin-Like Growth Factor I