Relation of rat fetal body weight to the relative expression of insulin genes I and II

This study investigates the relation between the ratio of the abundance of mRNAs encoded by insulin genes I and II (insulin I/II mRNA ratio) and the w eight of rat fetuses on gestational day 20. Total RNA was extracted from th e pancreas of the fetuses with the maximum and minimum body weight in each litter on gestational day 20. The amount of insulin mRNAs I and II in each RNA preparation was determined by reverse transcription-polymerase chain re action (RT-PCR) analysis and restriction enzyme digestion. The maximum and minimum weight of the fetuses were 4.07 +/- 0.23 and 3.23 +/- 0.34 g, respe ctively (N = 18, P < .01) and the corresponding insulin I/II mRNA ratios we re 3.65 +/- 0.55 and 1.42 +/- 0.21 (N = 18, P < .01). Furthermore, the insu lin I/II mRNA ratio correlated significantly with fetal weight (r = .526, P < .05). These results suggest that the relative expression of insulin gene s I and II may affect the extent of fetal growth. Copyright (C) 2000 by W.B . Saunders Company.