A method for the ureteral catheterization and the determinaton of the glomerular filtration rate in rats: with some applications on the study of parathyroids.

Most of the studies on the relation between parathyroids and the renal tubular reabsorption of phosphorus have been done in human subjects(Kleeman and Cook, 1951; Kyle et al., 1957, and many others)or in dogs(Hogben and Bollman, 1951; Foulks and Perry, 1959; Samiy et al., 1960, and many others). Many of them employed an insufficient number of humans or animals for statistical analyses of the experimental results. This seems to be one of the causes of the previous confusion in this field. On the other hand, there are few who tried the renal clearance studies using rats, because accurate and rapid determination of glomerular filtration rate(GER)in such small animals as rats has been difficult. There are many reports available on the changes in urinary phosphorus excretion in rats after parathyroidectomy(Talmage and Kraintz, 1954; Beutner and Munson, 1960, and many others)or after the injection of parathyroid extract(PTE)(Talmage et al., 1955; Kenny and Munson, 1959, and many others). However, changes in phosphorus excretion may be due to nonspecific changes in GFR, for an increase in GFR after the injection of PTE(jahan and Pitts, 1948; Handler et al., 1951, Hogben and Bollman, 1951)and a decrease in GFR after parathyroidectomy(Foulks and Perry, 1959)were reported. The present author established a method for the ureteral catheterization and for the rapid determination of GFR in rats which are very convenient animals in a laboratory work. It is a great advantage, furthermore, that rats can easily be fed on a synthetic diet phosphorus and calcium contents of which are conditioned. This enabled the author to study the effect of parathyroidectomy on the renal tubular reabsorption of phosphorus in rats.