Effects of cholecalciferol or calcium deficiency on oestrogen metabolism in the laying hen.
1. Seventeen 32-week-old White Leghorn laying hens were induced to become deficient in calciferol or in calcium (laying thin or soft shelled eggs) by withdrawing either cholecalciferol (27.5 micrograms/kg diet) or calcium (31 g/kg diet) supplements from the control diet. 2. The metabolic fate and metabolic clearance rate (MCR) of intravenously injected 3H-oestradiol-17 beta were then monitored for 40 min. 3. In both the calciferol and calcium-deficient groups a major oestrogen sulphate pathway was particularly affected, resulting in a decreased conversion of oestradiol-17 beta-3-sulphate to oestradiol-17 alpha-3-sulphate, with a concomitant reduced MCR of oestradiol-17 beta from plasma. 4. The metabolic defect was corrected by feeding the control diet. 5. Because the metabolic defect observed in calciferol deficiency occurred in Ca deficiency in a more severe form, we conclude that the more immediate cause was calcium rather than calciferol deficiency. To our knowledge, this is the first observation of a calcium-deficient effect on oestrogen sulphate metabolism in vivo.
Tsang
C P
CP
Animal Research Centre, Agriculture Canada, Ottawa, Ontario.
Grunder
A A
AA
Soares
H
H
Narbaitz
R
R
D000818:Animals; D002118:Calcium / Q000172:deficiency*; D002645:Chickens / Q000378:metabolism*; D002762:Cholecalciferol / Q000172:deficiency*; D004958:Estradiol / Q000378:metabolism*; D005260:Female; D010058:Oviposition; D011201:Poultry Diseases / Q000378:metabolism*; D014808:Vitamin D Deficiency / Q000378:metabolism / Q000662:veterinary*
D002762:Cholecalciferol; D004958:Estradiol; D002118:Calcium