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Circulating insulin-like growth factors-I and -II and substrates in fetal sheep following restriction of placental growth

Version 2 2024-06-05, 02:02
Version 1 2019-01-16, 14:59
journal contribution
posted on 2024-06-05, 02:02 authored by Julie OwensJulie Owens, KL Kind, F Carbone, JS Robinson, PC Owens
To determine the relationship between placental delivery of oxygen and glucose, circulating insulin-like growth factors (IGFs) and fetal growth, the effect of variable restriction of placental growth was determined in sheep in late gestation. Arterial blood was obtained via indwelling catheters at 120 and 127 days of gestation, prior to necropsy at 130 days to measure fetal and placental weights. Plasma was acidified and subjected to size-exclusion high-performance liquid chromatography at pH 2.8 to dissociate and separate IGFs from their binding proteins. The acid-dissociated IGF fraction was analysed by sensitive and highly specific radioligand assays for IGF-I and IGF-II, previously defined using ovine IGFs. Fetal weight and blood pO2 and glucose at 120 and 127 days of gestation correlated positively with placental weight. Plasma IGF-I was positively associated with fetal weight and fetal liver weight, and with blood pO2 and glucose at both ages. Plasma IGF-II levels also correlated positively with fetal weight, fetal liver weight and with blood glucose and pO2, but only at 127 days of gestation. In the most severely growth-retarded fetal sheep, blood glucose and pO2 and plasma IGF-I were significantly reduced when compared with normal fetuses at 120 days. All decreased further by 127 days of gestation as did plasma IGF-II in severely growth-retarded fetal sheep compared with normal fetuses. These observations are consistent with the hypothesis that both IGF-I and IGF-II are chronically regulated by oxygen and nutrition in utero and mediate part of the influence of placental supply of substrate over fetal growth.

History

Journal

Journal of endocrinology

Volume

140

Pagination

5-13

Location

Bradley Stok, Eng.

ISSN

0022-0795

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

1994, Journal of Endocrinology Ltd

Issue

1

Publisher

Bioscientifica