Abstract
The effects of dietary P intake and testosterone secretion on Ca, Mg and P metabolism were investigated in weanling male Wistar rats. The rats were divided into two groups, and one group was orchiectomized 4 days before administration of an experimental diet. The rats were then fed two levels of P (0.5% and 1.5% P) in the diet for 24 days. Dietary P levels were controlled with K5P3O10. Both intact and orchiectomized rats fed a high-P diet showed a decrease of urinary Ca excretion in the 5 days before dissection. Contents of renal Ca, Mg and P were increased by feeding the high-P diet and orchiectomy. Orchiectomy decreased the concentration of Mg and P, but not that of Ca, in serum. No effects were observed on contents of Ca and P per gram of dried femur. Furthermore, the concentration of serum parathyroid hormone was increased, whereas urinary excretion of cAMP was decreased, in rats orchiectomized and fed a high-P diet.
