Characterization of somatomedins from human fetal brain: identification of a variant form of insulin-like growth factor I.

Sara, Vicki R.; Carlsson-Skwirut, Christine; Andersson, Charlotte; Hall, E S; Sjögren, Benita; Holmgren, Arne; Jörnvall, Hans

doi:10.1073/pnas.83.13.4904

Cited by 151 publications

(65 citation statements)

References 18 publications

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“…In adult human cerebrospinal fluid and brain, IGF-II, but not IGF-I, was found (12,13). However, a truncated form of IGF-I as well as IGF-II was recently isolated from fetal and adult human brain (14,15). Evidence for local synthesis in pituitary and brain (13,16) suggests a physiological role for IGF-II as a neuroregulator and/or a brain growth factor.…”

Section: Ipmentioning

confidence: 99%

Tissue-specific expression of insulin-like growth factor II mRNAs with distinct 5' untranslated regions.

Irminger¹,

Rosen²,

Humbel³

et al. 1987

Proc. Natl. Acad. Sci. U.S.A.

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We have used RNA from human hypothalamus as template for the production of cDNAs encoding insulin-like growth factor II (IGF-II). The prohormone coding sequence of brain IGF-II RNA is identical to that found in liver; however, the 5' untranslated sequence of the brain cDNA has no homology to the 5' untranslated sequence of the previously reported liver cDNAs. By using hybridization to specific probes as well as a method based on the properties of RNase H, we found that the human IGF-II gene has at least three exons that encode alternative 5' untranslated regions and that are expressed in a tissue-specific manner. A probe specific to the brain cDNA 5' untranslated region hybridizes to a 6.0-kilobase transcript present in placenta, hypothalamus, adrenal gland, kidney, Wilms tumor, and a pheochromocytoma. The 5' untranslated sequence of the brain cDNA does not hybridize to a 5.3-kilobase transcript found in liver or to a 5.0-kb transcript found in pheochromocytoma. By using RNase H to specifically fragment the IGF-II transcripts into 3' and 5' fragments, we found that the RNAs vary in size due to differences in the 5' end but not the 3' end.

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Section: Ipmentioning

confidence: 99%

Tissue-specific expression of insulin-like growth factor II mRNAs with distinct 5' untranslated regions.

Irminger¹,

Rosen²,

Humbel³

et al. 1987

Proc. Natl. Acad. Sci. U.S.A.

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“…Sara et al (21,22) first identified a fetal somatomedin with characteristics different from those of adult IGF and more recently showed, using a fetal brain membrane radioreceptor assay, that circulating IGF levels of human fetuses between 16 and 28 wk of gestation include two components: IGF 2, and a "trun-0.1 1 versus 1.50 f 0.07).…”

Section: Resultsmentioning

confidence: 99%

Serum Insulin-Like Growth Factor 1 and Serum Growth-Promoting Activity during the First Postnatal Year in Infants with Intrauterine Growth Retardation

et al. 1988

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ABSTRAa. Follow-up from birth to age 12 months was obtained in 21 infants born with intrauterine growth retardation. Serum insulin-like growth factor 1 was measured by radioimmunoassay. The bioassayable growth-promoting activity of the serum was measured as the "thymidine activity" on lectin-activated lymphocytes at 5 days and 1, 3, 6, 9, and 12 months, and was compared with control values. Depending on their length at age 12 months, the intrauterine growth retardation infants were divided into three groups: at or above the average (n = 8, group A), between the mean and -2 SD (n = 7, group B), or less than -2 SD (n = 6, group C). No differences in nutritional indexes or in head circumference were found between the three groups. Insulin-like growth factor 1 was significantly lower at age 5 days in intrauterine growth retardation than in control infants. It increased slowly in groups A and B to reach the control values at age 9 and 12 months. In group C it remained significantly subnormal at 1 yr of age. Thymidine activity was also significantly lower at age 5 days in intrauterine growth retardation compared with control infants. It increased sharply at age 1-3 months in groups A and B but remained significantly lower in group C up to 1 yr of age. Although individual values of insulinlike growth factor 1 and thymidine activity were closely correlated, the increase of length during the first postnatal year correlated significantly with the thymidine activity levels at 1 and 3 months but not with the insulin-like growth factor 1 levels at 1, 3, and 6 months. These data may be of some physiological significance for understanding the postnatal catch-up growth occurring after intrauterine growth retardation. (Pediatr Res 24: 380-383, 1988) Abbreviations IGF 1, insulin-like growth factor 1 TA, thymidine activity of serum IUGR, intra-uterine growth retardation SFD, small-for-dates newborns SGA, small for gestational age newborns AGA, appropriate for gestational age newborns that occurs in most but not all IUGR infants, usually in early postnatal life. The predictive value of various prenatal and neonatal parameters has been extensively discussed. However, although several studies have shown that somatomedin C/IGF l levels are lower in SFD than in normal-for-dates newborns (10-13), no longitudinal data on serum IGF 1 values in IUGR infants have been reported. The aim of this study was to follow the evolution of serum IGF 1 measured by radioimmunoassay and of the serum growth-promoting activity measured using a previously published bioassay (1 4) over a I -yr period in a group of IUGR infants compared to normal age-matched controls. PATIENTS AND METHODSA total of 21 infants (I 1 males and 10 females) with birth weight less than -2 SD according to Usher and McLean (15) was followed, up to the age of 12 months, with measurements of IGF 1 and TA at ages 5 days and 1, 3,6,9, and 12 months. The gestational age, birth weight, and birth length of the 21 IUGR infants are shown in Figure 1. The gestational age was between 37 an...

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“…We have previously reported the isolation of a potent, N-terminally truncated form of IGF-I, des-(1-3)-IGF-I, from bovine colostrum , while others have also isolated this protein from human brain (Sara et al 1986, Carlsson-Skwirut et al 1987. Hence, we were interested to know whether such a species exists in kangaroo serum.…”

Section: Discussionmentioning

confidence: 99%

Purification, amino acid sequence and characterisation of kangaroo IGF-I

Yandell

Francis²,

Wheldrake³

et al. 1998

Journal of Endocrinology

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Insulin-like growth factor-I (IGF-I) and IGF-II have been purified to homogeneity from kangaroo (Macropus fuliginosus) serum, thus this represents the first report of the purification, sequencing and characterisation of marsupial IGFs. N-Terminal protein sequencing reveals that there are six amino acid differences between kangaroo and human IGF-I. Kangaroo IGF-II has been partially sequenced and no differences were found between human and kangaroo IGF-II in the 53 residues identified. Thus the IGFs appear to be remarkably structurally conserved during mammalian radiation. In addition, in vitro characterisation of kangaroo IGF-I demonstrated that the functional properties of human, kangaroo and chicken IGF-I are very similar. In an assay measuring the ability of the proteins to stimulate protein synthesis in rat L6 myoblasts, all IGF-I proteins were found to be equally potent. The ability of all three proteins to compete for binding with radiolabelled human IGF-I to type-1 IGF receptors in L6 myoblasts and in Sminthopsis crassicaudata transformed lung fibroblasts, a marsupial cell line, was comparable. Furthermore, kangaroo and human IGF-I react equally in a human IGF-I RIA using a human reference standard, radiolabelled human IGF-I and a polyclonal antibody raised against recombinant human IGF-I. This study indicates that not only is the primary structure of eutherian and metatherian IGF-I conserved, but also the proteins appear to be functionally similar.

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Characterization of somatomedins from human fetal brain: identification of a variant form of insulin-like growth factor I.

Cited by 151 publications

References 18 publications

Tissue-specific expression of insulin-like growth factor II mRNAs with distinct 5' untranslated regions.

Tissue-specific expression of insulin-like growth factor II mRNAs with distinct 5' untranslated regions.

Serum Insulin-Like Growth Factor 1 and Serum Growth-Promoting Activity during the First Postnatal Year in Infants with Intrauterine Growth Retardation

Purification, amino acid sequence and characterisation of kangaroo IGF-I

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