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Insulin-Like Growth Factors
Published in Jason Kelley, Cytokines of the Lung, 2022
Alan D. Stiles, Billie M. Moats-Staats, George Z. Retsch-Bogart
The IGF-I transcripts are found in greater abundance postnatally and, with the exception of brain, are present at a higher level than IGF-II in all postnatal tissues. Either growth hormone deficiency or malnutrition will result in decreased IGF-I gene expression. The reduction in expression is seen as decreased IGF-I transcript and peptide concentrations in numerous organs and is reflected by decreased serum concentrations of IGF-I peptide. Administration of growth hormone or correction of malnutrition results in normalized IGF-I tissue and serum concentrations. Effects on IGF-I expression by other hormones within specific tissues have been described. For example, estrogen enhances IGF-I gene expression in the uterus (Murphy and Friesen, 1988) and parathyroid hormone (as well as growth hormone) stimulates IGF-I gene expression in cartilage (Canalis et al., 1989). Placental lactogen likely affects IGF-I gene expression in the fetus, acting as a growth hormone homologue (Hill et al., 1986, 1988).
Lifestyle Factors in Cancer Survivorship
Published in Pat Price, Karol Sikora, Treatment of Cancer, 2020
Insulin-like growth factor (IGF-1) and its binding proteins, insulin-like growth factor binding proteins (IGFBPs), have a central role in the regulation of cell growth. After binding to its receptor tyrosine kinase, IGF-1 activates several signaling pathways, leading to the inhibition of apoptosis, the promotion of cell growth, and angiogenesis. Higher levels of IGF-1 would therefore be expected to increase tumor growth and have been reported to be associated with a greater cancer risk. An inverse relationship is reported with IGF binding protein (IGFBP3) levels, although this effect has not been confirmed in all studies. Exercise has been shown to increase the levels of IGFBP3 and lower IGF-1, and in a large prospective cohort study of 41,528 participants, this was associated with a 48% reduction of cancer-specific deaths. Decreased levels of IGF-1 in physically active patients have also been linked to an improved survival.
Pituitary Gland
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
Many of the growth and metabolic effects of GH are mediated by somatomedins or insulin-like growth factor (IGF) (IGF-1 and IGF-2). The IGF receptors are high-affinity membrane receptors that are tyrosine kinases similar to those of insulin. IGF-1 mediates growth (mitosis) and differentiation. It acts as a mitogen by stimulating DNA, RNA, and protein synthesis.
Growth factors in anorexia nervosa: a systematic review and meta-analysis of cross-sectional and longitudinal data
Published in The World Journal of Biological Psychiatry, 2022
Johanna Louise Keeler, Lauren Robinson, Rosemarie Keeler-Schäffeler, Bethan Dalton, Janet Treasure, Hubertus Himmerich
Our findings have shown that individuals with AN have lower levels of IGF-1 compared to controls. In the longitudinal analyses, concentrations of IGF-1 were greater at follow-up compared to baseline, indicating that these growth factors normalise following treatment and partial weight restoration. IGF-1 is an anabolic hormone produced mainly by the liver, which is stimulated by and mediates the effects of growth hormone (Sara and Hall 1990). In AN, reductions in IGF-1 have been closely linked with impaired bone density (Soyka et al. 1999; Audi et al. 2002). IGF-1 has an overall positive influence on cell growth in signalling to cells that sufficient nutrients are available for proliferation and differentiation, whilst also preventing apoptosis (i.e. programmed cell death) and cell degradation (Bikle et al. 2015).
Bone Turnover Markers and Bone Histomorphometry in Pubertal Rats with Intrauterine Growth Restriction
Published in Fetal and Pediatric Pathology, 2021
Kaiju Luo, Pingyang Chen, Mingfeng He, Yonghui Yang, Juncao Chen, Tao Wang
Our study also showed that serum IGF-1 were lower in the IUGR group than in the control group at 7 d and 21 d. IGF-1 is one of the most abundant growth factors in bone tissue. Studies have established critical osteogenic roles for IGFs in bone growth. Serum IGF-1 concentration has been found to be associated with BMD and fracture risk in various ethnic groups [30]. Decreased IGF-1 levels in patients with osteoporosis are closely related to cytokines and bone mineral density and may participate in the pathogenesis of osteoporosis [31]. Fetuses and neonates, energy and protein are the most important regulatory factors of serum IGF-1 because of an immature growth hormone (GH)/IGF-1 axis. Thus, we concluded that protein restriction in pregnancy resulted in low levels of serum IGF-1 in IUGR rat pups from birth to the end of breastfeeding, and decreased IGF -1 inhibited osteoblast activity and bone formation in early life, which is one of the important mechanisms contributing to the postnatal bone metabolic disorders of IUGR rat pups.
The association between insulin-like growth factor 1 levels within reference range and early postoperative remission rate in patients with Cushing’s disease
Published in Endocrine Research, 2021
Emre Gezer, Berrin Çetinarslan, Alev Selek, Zeynep Cantürk, Mehmet Sözen, Özlem Elen, Canan Baydemir, Burak Çabuk, Savaş Ceylan
To date, Gourmelen et al. 21 conducted the largest study evaluating IGF-1 level in patients with CD. Forty-nine patients were examined and IGF-1 levels were not significantly different from healthy adults. Similarly, two other studies have demonstrated normal IGF-1 levels in CD.5,20 The latter evaluated 12 patients with Cushing’s syndrome and their IGF-1 levels were slightly elevated (195 ± 34 ng/mL), but still within the reference rage and similar to the concentration found in the control group (190 ± 20 ng/mL), in accordance with our data. In contrast, one of the most recent studies, reported by English et al.6 in 2019, examined 25 patients with CD and compared them with 49 controls. The mean IGF-1 level in the CD group was significantly higher than the control group (p = .005) and in 13 patients who achieved postoperative remission, IGF-1 levels decreased significantly.