Interaction between malnutrition and ovarian hormones on the systemic IGF-I axis

Abstract

Objective: In malnutrition both the GH -IGF and reproductive axes are greatly affected. Because the actions of IGF and sex steroids are inter-dependent in many tissues, we have examined how ovariectomy modulates the response of the systemic IGF system to undernutrition. Design and methods: Peripubertal (30 days of age) female rats were either sham operated or ovariectomized. Five days later half of each group was submitted to a protein-caloric restriction diet. All rats were killed at 60 days of age. Results: Growth was decreased in all rats submitted to calorie restriction and this was consistent with a decrease in circulating IGF-I concentrations and liver IGF-I mRNA expression. While in normally fed rats ovariectomy had no significant effect on serum IGF-I concentrations, ovariectomized and underfed rats had significantly higher levels than intact underfed rats. In undernourished rats, serum IGF-binding proteins (IGFBP)-1, -2 and -3 concentrations were significantly reduced and this was not modified by ovariectomy. In contrast, liver mRNA concentrations of IGFBP-1 and -2 were increased and IGFBP-3 unchanged in intact undernourished animals, suggesting that undernutrition could be affecting the proteolysis of these binding proteins, and this response was significantly modulated by ovariectomy. Conclusion: These results indicate that the presence of circulating ovarian hormones significantly affects the response of the IGF system to undernutrition.

Maternal nutrient restriction during early to mid gestation up-regulates cardiac insulin-like growth factor (IGF) receptors associated with enlarged ventricular size in fetal sheep

“…Circulating IGFBP levels may be affected by nutritional and catabolic states. Calorierestriction has been shown to increase IGFBP-1 and IGFBP-2, whereas decrease IGFBP-3 levels [42]. However, our results suggested that local ventricular expression of IGFBP-3 may not be affected in the same manner as the circulating IGFBP-3.…”

“…However, our results suggested that local ventricular expression of IGFBP-3 may not be affected in the same manner as the circulating IGFBP-3. Since undernutrition may cause a significant reduction in serum IGF-1 levels [42], the upregulation of ventricular IGF receptor may be a compensatory mechanism to ''make up'' for the heart growth at early stage of gestational nutrient deficiency. However, with persistent nutrient deficiency and over expressed IGF receptor, the effect of IGF cascade on heart development may switch from a compensatory beneficial effect to the detrimental hypertrophic one.…”

Postnatal reorganization of primary afferent terminal fields in the rat gustatory brainstem is determined by prenatal dietary history

“…Previous studies show similar trends for the relationship of malnutrition and brain IGF in other brain areas. For example, refeeding following food restriction leads to high levels of IGF-1 that persist into postnatal development and prolong the normal developmental time course (Chowen et al, 2002; Goya et al, 2002). A similar event may occur following sodium repletion at E12, potentially resulting in molecular/cellular alterations in the NTS that change the normal development of primary afferent terminal fields.…”

Successful Treatment of Dwarfism Secondary to Long-term Steroid Therapy in Steroid-Dependent Nephrotic Syndrome

“…In addition, there are many other related factors in serum, including calcium, 25-hydroxyvitamin D3, and thyroid hormone, which are combined and lost in urine with their associated binding proteins; all of the above exert effects on growth. Malnutrition or hypoproteinemia is another important cause of growth retardation in NS children (17), which is still poorly understood. "Catch-up growth", known as the phenomenon that the linear growth rate usually exceeds the normal range, was observed after a period of growth inhibition.…”