IGF-II and IGF-binding proteins increase dramatically during rabbit pregnancy

Cartilage is a primary target tissue for the IGFs. The mitogenic activity of these peptides is regulated by a family of high-affinity IGF-binding proteins (IGFBP-1 to -6). We characterized the IGFBPs produced by cultured chondrocytes derived from rib cartilage of prepubertal rabbits. Culture medium, which had been conditioned by these cells for 48 h showed bands of 22 kDa, 24 kDa and a 31/32 kDa doublet by Western ligand blotting with [ 125

Section: Characterization Of Secreted Igfbps and Regulation By Igfsmentioning

confidence: 99%

Differential regulation of IGF-binding proteins in rabbit costal chondrocytes by IGF-I and dexamethasone

Koedam

Hoogerbrugge²,

Buul-Offers³

2000

“…During pregnancy, maternal plasma levels of IGF-I increase early in most species (Wilson et al 1982, Gargosky et al 1990, Donovan et al 1991, Hills et al 1996, Nason et al 1996, Sohlström et al 1998b. The abundance of circulatory IGF-II increases in some species (Nason et al 1996), including humans (Wilson et al 1982, Gargosky et al 1990), but remains unchanged in others (Donovan et al 1991, Sohlström et al 1998b.…”

Section: Introductionmentioning

confidence: 99%

“…The abundance of circulatory IGF-II increases in some species (Nason et al 1996), including humans (Wilson et al 1982, Gargosky et al 1990), but remains unchanged in others (Donovan et al 1991, Sohlström et al 1998b. On the one hand, results from rat studies indicate that maternal serum IGF-I targets the mother's own anabolism and substrate retention rather than the foetus (Gargosky et al 1991, Monaco & Donovan 1996.…”

Section: Introductionmentioning

confidence: 99%

Effects of food restriction and pregnancy on the expression of insulin-like growth factors-I and -II in tIssues from guinea pigs

Olausson¹,

Sohlström²

2003

The insulin-like growth factor (IGF) system is subjected to pregnancy-associated changes in the circulation and is suggested to be of importance for partitioning of nutrients between the mother and the foetus. Interestingly, maternal undernutrition alters the pregnancy-associated changes, with possible adverse consequences for the mother and the foetus. However, it is not known how malnutrition and pregnancy alter the expression of mRNA for IGFs locally in different tissues. The aims of this study were to investigate where IGF-I and IGF-II are expressed in guinea pigs and how this expression is altered during food restriction and pregnancy. Ad libitum-fed and foodrestricted (fed 70% of the ad libitum-fed intake four weeks before pregnancy and throughout the study) guinea pigs were mated. On day 40 of pregnancy and on the corresponding day for virginal females the animals were killed. mRNA for IGF-I and IGF-II was analysed in various organs/tissues by solution hybridisation. mRNA for IGF-I was expressed in high amounts in uterus, liver and adipose tissues. The expression was not affected by food restriction, but was increased in liver and adipose tissue and decreased in uterus by pregnancy. mRNA for IGF-II was expressed in high amounts in the placenta and liver. In the placenta the expression was decreased by food restriction. Pregnancy increased the levels of mRNA for IGF-II in the liver. Food-restricted dams had smaller foetuses and placentas. In conclusion, this study indicates an important role for the adipose tissue during gestation, not only as an energy store but also as an endocrine tissue expressing IGF-I. The decreased expression of IGF-II in the placenta due to food restriction is suggested to have adverse effects on placental structure and function.

“…Maternal blood concentrations of GH, IGF-I and/or IGF-II are increased during early or throughout all of pregnancy in a number of mammalian species (Donovan et al 1991, Gargosky et al 1990, Hills et al 1996, Kelly et al 1976, Mirlesse et al 1993, Nason et al 1996, Owens 1991, Sinha et al 1990. Intrauterine growth retardation is associated with lower than normal concentrations of GH and IGF-I in maternal plasma in humans (Chowden et al 1996, Lassarre et al 1991, Mirlesse et al 1993, whilst GH-deficiency in dams impairs fetal growth in rats (Spencer et al 1994).…”

Section: Introductionmentioning

confidence: 99%

Treatment of underfed pigs with GH throughout the second quarter of pregnancy increases fetal growth

Gatford

Owens

Campbell

et al. 2000

Circulating growth hormone (GH) concentrations increase in pregnancy and administration of GH during early-mid pregnancy increases fetal growth in well-fed pigs. To determine whether increased maternal GH could promote fetal growth when feed availability is restricted, fifteen cross-bred primiparous sows (gilts) were fed at approximately 30% of ad libitum intake, from mating onwards and were injected daily i.m. with recombinant porcine GH (pGH) at doses of 0, 13·4 0·3 and 25·6 0·5 µg/kg live weight from day 25 to day 51 of pregnancy (term 115 days). Treatment with pGH increased maternal backfat loss between day 25 and day 51 of pregnancy, and increased maternal plasma IGF-I concentrations measured at day 51 of pregnancy. Fetal body weight, length and skull width at day 51 of pregnancy were increased by maternal treatment with pGH. Fetal plasma glucose concentrations were increased and maternal/fetal plasma glucose concentration gradients were decreased by maternal pGH treatment at 13·4, but not 25·6 µg/kg.day. Fetal plasma concentrations of urea were decreased by both levels of pGH treatment. Overall, fetal weight was negatively correlated with fetal plasma concentrations of urea, positively correlated with maternal plasma -amino nitrogen concentrations and unrelated to glucose concentrations in either maternal or fetal plasma. This suggests that the availability of amino acids, not glucose, limits fetal growth in the first half of pregnancy in underfed gilts, and that maternal GH treatment may improve amino acid delivery to the fetus.