Vascular actions of the calcium-regulating hormones.
The vascular actions of the hormones that participate in the regulation of whole animal calcium (Ca2+) homeostasis and related factors are discussed. Parathyroid hormone (PTH) has vasodilator activity that is mediated by a specific cell membrane receptor coupled to adenylate cyclase and thus increases intracellular cAMP and lowers intracellular Ca2+. The peptide may also block voltage-sensitive Ca2+ channels. However, the general consensus is that PTH does not achieve sufficient levels in the serum to modulate vascular reactivity. Parathyroid hormone does, however, share a common receptor and N-terminal amino acid sequence homology with parathyroid hormone-related peptide (PTHrp), which has many of the properties of a locally acting vascular regulator. Exciting actions of the steroid hormone, 1,25(OH)2 vitamin D3, have recently been described which suggest that the hormone is a vascular smooth muscle-differentiating agent and promises to set the stage for learning about the long-term modulatory actions of other steroid hormones. Calcitonin has minimal vascular actions, and although CGRP is not classifiable as a Ca(2+)-regulating hormone, it is a potent vasodilator neurotransmitter. Finally, within the past 2 years there has been a ground swell of activity surrounding the existence of the extracellular Ca2+ receptor that senses changes in interstitial Ca2+. The response of the smooth muscle cell to extracellular Ca2+ is discussed in the context of this receptor.
Bukoski
R D
RD
Department of Internal Medicine, University of Texas Medical Branch, Galveston Island 77555-1065, USA.
Ishibashi
K
K
Bian
K
K
D000818:Animals; D002112:Calcifediol / Q000494:pharmacology; D002116:Calcitonin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D006801:Humans; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D010281:Parathyroid Hormone / Q000737:chemistry / Q000494:pharmacology*; D010446:Peptide Fragments / Q000737:chemistry / Q000494:pharmacology; D011817:Rabbits; D051381:Rats; D014655:Vascular Resistance / Q000187:drug effects
D010281:Parathyroid Hormone; D010446:Peptide Fragments; D002116:Calcitonin; D002112:Calcifediol; D002118:Calcium