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Full-Text Articles in Poultry or Avian Science

Rapid Effects Of 25-Hydroxyvitamin D3 On Calcium Uptake In Isolated Chick Enterocytes, Ruta Phadnis May 2003

Rapid Effects Of 25-Hydroxyvitamin D3 On Calcium Uptake In Isolated Chick Enterocytes, Ruta Phadnis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

25-Hydroxyvitamin D3[25(OH)D3] is a metabolite of vitamin D3 that has long been considered to be an inactive precursor of the hormonally active metabolite 1,25- dihydroxyvitamin D3[l,25(OH)2D3]; consequently very few studies have addressed the potential biological activity of 25(OH)2D3. However, it is known that 100 nM 25(OH)2D3 increases calcium transport in the perfused duodenal loop of the chicken to 200% of controls within 20 minutes. The hypothesis of the current study is that 25(OH)2D3 may be a hormonally active metabolite …


Physiological Importance Of 1,25(Oh)2D3 Membrane-Initiated And Nuclear Actions In Chickens As A Function Of Growth, And Maturation In Male And Female Chickens, Birgitta Larsson May 2002

Physiological Importance Of 1,25(Oh)2D3 Membrane-Initiated And Nuclear Actions In Chickens As A Function Of Growth, And Maturation In Male And Female Chickens, Birgitta Larsson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

It is well established that l,25(OH)2D3 is a major regulator of calcium homeostasis. The steroid exerts its effects on its target organs by two mechanisms, a slow mechanism mediated by nuclear vitamin D receptors (nVDR), and a rapid mechanism mediated by the l,25(OH)2D3 membrane-associated rapid response steroid binding protein (l,25D3-MARRS bp). In this dissertation, the physiological relevance of membrane initiated steroid signaling was investigated by studying the correlation of age in male and female chickens with the magnitude of responses to l,25(OH)2D3 in duodena from 7-, 14-, 28-, and …