Role of fibroblast growth factor-23 in the regulation of calcium metabolism in lactating rats and potential application as a biomarker in the assessment of body calcium status during lactation
1. To determine correlations between intestinal production of FGF-23 and histological changes in different segments of maternal intestine during lactation. The specific sub-objectives are:
1.1 To study histological changes in all intestinal segments of maternal intestine during lactation by using histomorphometric technique.
1.2 To study FGF-23 protein expression in all intestinal segments of maternal intestine.
2. To investigate the acute and long-term effects of hyperprolactinemia on local expression of FGF-23 in the intestine and systemic changes in plasma FGF-23. In this part, the specific sub-objectives are:
2.1 Local response: we study changes in the FGF-23 expression by using in vitro and in vivo models.
2.1.1 In vitro model: to investigate the acute and long-term effects of PRL on the expressions of FGF-23 in Caco-2 cells.
2.1.2 In vivo model: to investigate the acute and long-term effects of hyperprolactinemia on the expressions of FGF-23 in the intestine of female rats.
2.2 Systemic response: to investigate the acute and long-term effects of hyperprolactinemia on the plasma FGF-23 level in female rats.
3. To evaluate a possibility to use FGF-23 as a biomarker for determining calcium status in normal and lactating rats. In this part, the specific sub-objectives are:
3.1 To determine changes of plasma FGF-23 in male and female rats subjected to oral calcium supplement via a gavage tube.
3.2 To determine changes of plasma FGF-23 levels in lactating rats subjected to oral calcium supplement via a gavage tube.
3.3 To determine changes of plasma FGF-23 levels in pre- and post-suckling periods in lactating rats with or without oral calcium supplement via a gavage tube.
