AJP - Endocrinology and Metabolism, Vol 247, Issue 4 442-E448, Copyright © 1984 by American Physiological Society
Bioactive parathyroid hormone in canine progressive renal insufficiency
D. Grunbaum, M. Wexler, M. Antos, M. Gascon-Barre and D. Goltzman
Bioactive parathyroid hormone and hormonal actions were monitored as
hyperparathyroidism evolved in a model of progressive canine renal failure.
Circulating levels of bioactive and immunoreactive parathyroid hormone rose
as renal insufficiency worsened, but elevations, especially in bioactivity,
were most marked in the final stage of uremia. By gel filtration analysis,
the major circulating bioactive moiety was similar to the major glandular
form of parathyroid hormone, although a smaller-molecular-weight entity was
seen in the final stage of renal failure. Renal phosphate threshold fell,
urinary hydroxyproline corrected for glomerular filtration rose, and plasma
1,25-dihydroxyvitamin D fell but remained detectable, as renal function
deteriorated. The results demonstrate a progressive rise in bioactive
parathyroid hormone, show the appearance of a small-molecular-weight
bioactive entity in severe renal disease, and correlate effects of the
rising bioactive parathyroid hormone with changes in renal phosphate
handling and with skeletal resorption.
