AJP - Regulatory, Integrative and Comparative Physiology, Vol 255, Issue 4 635-R642, Copyright © 1988 by American Physiological Society
Parathyroid hormone-like immunoreactivity in brains of tetrapod vertebrates
P. K. Pang, S. Harvey, R. Fraser and T. Kaneko
Department of Physiology, University of Alberta, Edmonton, Canada.
Heat-stable nondialyzable immunoreactive (IR) parathyroid hormone
(PTH)-like activity, that coelutes with authentic PTH on Sep-Pak C18
columns and reverse-phase high-performance liquid chromatography, was
measured in the brain, hypothalamus, and pituitary of amphibian, reptilian,
avian, and mammalian species, using two specific antisera raised against
the 48-64 region of the intact PTH molecule. In each case the IR PTH
concentration was greater than that present in peripheral plasma and in
rats was not affected by dietary calcium status. Extracts of muscle, liver,
and kidney tissue were without IR PTH activity. These results demonstrate
the extraparathyroidal occurrence of PTH-like peptides in nontumorous
neuroendocrine tissues of vertebrate species. These findings may have
evolutionary significance, since IR PTH was present in the brain and plasma
of species that lack encapsulated parathyroid glands.
