Abstract
Insulin-like growth factor-II (IGF-II) is an important regulator of embryonic growth and differentiation, but its function in postnatal life is unclear. To address this point, we generated transgenic mice harboring fusion genes in which a human IGF-II complementary DNA is placed under the transcriptional control of the rat phosphoenolpyruvate carboxykinase promoter. Transgene-specific messenger RNA was detected in liver, kidney, and several parts of the gut. Serum IGF-II levels in transgenic mice were 2-3 times higher than those in controls and increased after starvation. Circulating IGF-I correlated negatively and IGF-binding protein-2 (IGFBP-2) positively with IGF-II levels, suggesting that IGF-I is displaced from IGFBPs by IGF-II and that IGFII is a major regulator of IGFBP-2. Serum levels of IGFBP-3 and IGFBP-4 tended to be higher in phosphoenolpyruvate carboxykinase- IGF-II transgenic mice than in controls, as evaluated by ligand blot analysis. Starvation reduced serum IGF-I, but increased IGFBP-2 in transgenic mice more markedly than in controls. Fasting insulin levels were significantly reduced in transgenic mice, whereas glucose levels were not influenced by elevated IGF-II. The body growth of 4- and 12- week-old mice was not significantly influenced by elevated IGF-II, but transgenic mice displayed increased kidney and testis weight at the age of 4 weeks, and increased adrenal weight at the age of 12 weeks. Our results demonstrate that elevated IGF-II in postnatal life has multiple endocrine consequences and subtle time-specific effects on organ growth.
Item Type: | Journal article |
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Form of publication: | Publisher's Version |
Faculties: | Medicine |
Subjects: | 600 Technology > 610 Medicine and health |
URN: | urn:nbn:de:bvb:19-epub-15955-9 |
ISSN: | 0013-7227 |
Alliance/National Licence: | This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively. |
Language: | English |
Item ID: | 15955 |
Date Deposited: | 18. Jul 2013, 14:07 |
Last Modified: | 04. Nov 2020, 12:57 |