| 1. |
- Isaksson, Olle, 1943, et al.
(författare)
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Regulation of cartilage growth by growth hormone and insulin-like growth factor I.
- 1991
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Ingår i: Pediatric nephrology (Berlin, Germany). - 0931-041X. ; 5:4, s. 451-3
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Tidskriftsartikel (refereegranskat)abstract
- A number of studies have shown that growth hormone (GH) and insulin-like growth factor-I (IGF-I) have important regulatory roles for skeletal growth. However, it has been a matter of controversy whether GH acts directly on cells in the growth plate or if the growth-promoting effects of GH are mediated by liver-derived (endocrine-acting) IGF-I. With the recognition that GH regulates the production of IGF-I in multiple extra-hepatic tissues, autocrine and paracrine functions of IGF-I have been suggested as important components of GH action. This review focuses on recent developments in our understanding of the cellular mechanisms by which GH promotes longitudinal bone growth and the inter-relationship between GH and IGF-I in the growth plate.
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| 2. |
- Ohlsson, Claes, 1965, et al.
(författare)
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The relative importance of endocrine versus autocrine/paracrine insulin-like growth factor-I in the regulation of body growth.
- 2000
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Ingår i: Pediatric nephrology (Berlin, Germany). - 0931-041X. ; 14:7, s. 541-3
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Tidskriftsartikel (refereegranskat)abstract
- Body growth is regulated by growth hormone (GH) and insulin-like growth factor-I (IGF-I). The classical somatomedin hypothesis of this regulation is that most IGF-I in the blood originates in the liver and that body growth is controlled by the concentration of IGF-I in the blood. We have recently abolished IGF-I production in the livers of mice by using the Cre/loxP recombination system. These mice displayed a more than 75% reduction in serum IGF-I associated with increased serum levels of GH. In contrast, they demonstrated a normal postnatal growth, indicating that extrahepatic, autocrine/paracrine-acting IGF-I is the main determinant of postnatal growth. Thus, the "classical" somatomedin hypothesis needs revision. We propose the "dual somatomedin hypothesis" according to which: (1) autocrine/paracrine IGF-I is the main determinant of postnatal body growth and (2) liver-derived, endocrine-acting, IGF-I exerts negative feedback on GH secretion and possibly also exerts other effects on carbohydrate and lipid metabolism.
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