Self-Regulation of Phosphate Intake in the Rat: The Influence of Age, Vitamin D and Parathyroid Hormone
Growing rats offered a choice of four pairs of diets, one low in P (0.1%) and the others containing 0.3, 0.6, 1.2 or 1.8% P, selected food mixtures in each case with nearly identical P contents (0.23–0.24%) (Ca:P = 2.2:1). Mature rats offered the same dietary choices exhibited less rigid diet selection but clearly preferred a diet higher in P (0.64–0.69%) (Ca:P = 0.9:1). Vitamin D-deficient animals selected less P than controls and parathyroidectomized rats severely limited their P intake. The increase in self-determined P consumption relative to Ca in mature rats is consonant with the greater decrease in the requirement for Ca associated with maturation and cessation of bone growth. Susceptibility to hypocalcemia in vitamin D deficiency and parathyroidectomy is a probable factor in the increased sensitivity to excess dietary P, which further depresses plasma Ca. These experiments confirm the existence of a feedback mechanism that regulates the voluntary consumption of P in accordance with physiological needs.
Chemistry and Geology
Journal of Nutrition
Siu, G.M., Hadley, M., Agwu, D.E., & Draper, H.H. (1984). Self-regulation of phosphate intake in the rat: The influcence of age, vitamin D and parathyroid hormone. The Journal of Nutrition, 114(6), 1097-1105. https://doi.org/10.1093/jn/114.6.1097
Publisher's Copyright and Source
Copyright © 1984 The American Institute of Nutrition.