| To evaluate the roles and mechanism of IGF-2 on fetal growth and development during late gestation, pregnant ewes and rats were employed to investigate relationship between IGF-2 and metabolites, hormones of pregnant animals and their fetuses. The dynamic variations in the plasma IGF-2, and its correlation with plasma hormones and metabolites in pregnant ewes with their fetuses and neonates as well as the growth and development of fetuses and neonates during perinatal period at normal condition and series of experiments (with IGF-2 fragment, glucose, insulin and cholic acid ) have been measured. The results showed as follows: 1. Relationuhlpbetwntheplauum IGF?and.utabolisu, horu,on.s lnpregnunt sheep durIng late gestation 6 comdale pregnant ewes were randomly allotted into CA group and control group after 2 weeks of adaptation. Before treatment, jugular vein catheters were installed. CA-treated group was infused with 2mg.kg~?cholic acid through jugular vein catheter and control group was administrated with the quantitative 0.9% saline. The next infusion was conducted on day 14 after front infusion until parturition. Blood samples were collected daily before and after infusion for assaying levels of plasma IGF-2, other hormones and metabolites, and calculating the correlation among them, as well as studying the effects of cholic acid loading on them. The results showed that the plasma IGF-2 levels in late gestational ewes varied between 36.25 ?1 .O2ng/ml -61.18 ? 1 3.6SngIml , without obvious dynamic changes, but a depressed tendency was found after parturition. Ewes in late gestation showed high levels of IGF-1, its average was significantly higher than that for post-parturition period. During that period the plasma IGF-2 positively correlated to plasma glucose, and the correlation between IGF-1 and glucose was negative. Cholic acid infusion caused elevation in plasma IGF-2, but a few days later decreased, near the partuntion again rose, and then kept high levels during post-parturition period. The average of plasma IGF-1 in CA group (625.28 ?85.S6nglml) was obviously lower than that of control (705.21 ?52.24ng/ml) during pre-parturition period. CA-treated ewes also showed higher plasma glucose and a-amino nireogen levels, as well as sharp elevations of plasma IGF-2, insulin and cortisol at partuntion 3 period. It was concluded that maternal plasma IGF-1 is a greater regulator of fetal growth during late gestation and may have physiological blood glucose-Iowed effect as like as insulin, while plasma IGF-2 is relative unimportant determiner in contrast to IGF- 1, and its concentration may be regulated by plasma glucose. The rise in plasma IGF-2, insulin and cortisol after CA infusion relate to the stress, dystocia or abortion, while decreased maternal IGF-1 is one reason for intrauterine growth retardation. 2. RelatIonship between the plau. ItF? and inmtabolitea, hornunes in pregnant owes, their fetuses and neonatal I.E. during prenatal period 7 ewes of certain gestation time were assigned into CA-treated (n=5) and control group (n=2), then 1.1 mg/kg of cholic acid or equivalent 0.9% saline were infused into the jugular vein of ewes on 90 and 104 days of gestation, respectively. Up to 120 days of gestation, all ewes and their fetuses were operatively installed jugular vein catheter for ewes and frontal tlbien artery catheter for fetuses. Blood samples were taken daily after the operation for analyzing IGF-2 and metabolites. Final fetal...
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