Localization of IGF-I in adult rats. Immunohistochemical studies.
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Animals↗
Biomedical subjects
A Skottner
Publications and source records attributed to A Skottner.
Evidence indicating trophic importance of IGF-I in regenerating peripheral nerves.
The mechanisms influencing regeneration of peripheral nerves are incompletely known, but growth factors are supposed to play a key role. In the present study, we demonstrate, with the aid of immunohistochemical methods, that somatomedin C (Sm-C/insulin-like growth factor I/IGF-I) rapidly increased from low to high concentrations, reaching peak values in 2 weeks, in regenerating sciatic nerves of adult rats. In addition, IGF-I was demonstrated extracellularly, never observed in the control nerves. Reactive Schwann cells appeared to be the major source for IGF-synthesis. Higher concentrations were seen in tubulated nerves as compared to sutured ones. It is proposed that IGF-I exerts important growth supporting effects on regenerating peripheral nerves.
Animals↗
Comparison of methionyl human growth hormone and pituitary growth hormone on somatic growth of hypophysectomized rats.
In hypophysectomized male rats the biological effects of two batches of methionyl human growth hormone, Somatonorm, (met-hGH), have been compared to those of human pituitary growth hormone, Crescormon (hGH). The rats were treated with doses ranging from 10 mIU per day to 145 mIU per day for 10 days. The parameters studied were total weight gain, longitudinal bone growth, measured by the tetracycline method and indirect cartilage growth, measured by uptake of radioactive sulphate. The results obtained demonstrated that Somatonorm stimulated weight increase in a linear and dose-dependent way, similar to that seen with the native hormone. Longitudinal bone growth, measured by the tetracycline method and the growth of different cartilages, measured as uptake of radioactive sulphate, were also similar between the two hormones.
Animals↗
Serum somatomedin A and non-dialyzable urinary hydroxyproline in girls with idiopathic scoliosis.
Serum somatomedin A was determined by radioreceptor assay in 31 girls with idiopathic scoliosis and 30 controls, with ages ranging from 9.7-16.2 years. In the material as a whole no significant difference could be found between scoliotics and controls. Similarly no differences were found in the girls under 13 years of age. However, in girls older than 13 years the controls had significantly higher somatomedin A levels than the scoliotics. In the second part of the study 26 girls with idiopathic scoliosis and 22 controls were examined with regard to the urinary excretion of non-dialyzable hydroxyproline,. which has been suggested to be correlated with collagen synthesis. The percentage non-dialyzable fraction of the total hydroxyproline was found to be significantly higher in the control girls. The mean age was 12.8 years for both groups. The results suggest a higher growth rate in the controls than in the scoliotics for girls over 12 years. There is, however, no definite evidence as to the function of the somatomedins or of the relationship between non-dialyzable hydroxyproline and growth.
Adolescent↗
Purified human somatomedin A and rat multiplication stimulating activity. Mitogens for cultured fibroblasts that cross-react with the same growth peptide receptors.
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Animals↗
Somatomedin A and B in serum from neonates, their mothers and cord blood.
Somatomedin A by radioreceptor assay and somatomedin B by radioimmunoassay were measured in serum from women immediately after parturition and from their newborns. The mean levels of somatomedin A in both mothers (0.54 U/ml) and infants (0.50 U/ml) were significantly decreased compared to a reference group consisting of 21 non-pregnant women (0.91 U/ml). There was no difference between the mothers and their children. The mean somatomedin B value in serum from the mothers (63.9 microgram/ml) was above that found in non-pregnant women (19.2 microgram/ml) and the mean value in cord blood and serum from the infants (7.1 microgram/ml) was below it. A positive correlation was noted between somatomedin A and B in cord blood; r = 0.78. The combined somatomedin A and B values in cord blood were positively correlated to birth weight (r = 0.51, P less than 0.05).
Birth Weight↗
Growth hormone treatment and development of malignancy: recombinant human growth hormone does not induce leukemia in AKR/O-mice.
In 1988 several reports described leukemia in former/present growth hormone (GH)-treated children, and a doubled incidence of leukemia in GH-treated children was concluded in a workshop in Bethesda. A mouse strain (AKR/O) with a high incidence of leukemia was used as a model. AKR/O-mice in the preleukemic adult age and younger mice during rapid growth were treated with recombinant human GH (rhGH) in human therapeutic doses to see whether this treatment would affect the time and presentation of malignant disease. The malignant development did not appear earlier or in a different way in the animals receiving rhGH from day 6 to 50 than in their appropriate controls. A borderline protective effect to the development of leukemia was seen in the adult group receiving rhGH; in this group antibodies to hGH also developed. We conclude that in this experimental model human therapeutic doses of rhGH do not influence the development of malignancy in the AKR/O mice.
Animals↗