Pathogenic Role of Cyclic AMP in the Impairment of Urinary Concentrating Ability in Acute Hypercalcemia
AUTOR(ES)
Beck, Nama
RESUMO
A possible association between the impairment of urinary concentrating ability and an impairment of the vasopressin-dependent cyclic AMP system in hypercalcemia was investigated in rat kidneys both in vivo and in vitro. The increases of urinary osmolality and negative free water clearance and the increase of urinary cyclic AMP excretion by vasopressin injection were significantly less in the hypercalcemic rats than in the control rats. The increase of cyclic AMP concentration by vasopressin in renal medullary tissue was significantly less in the slices obtained from the hypercalcem'c rats than in those obtained from the control rats. The activation of adenylate cyclase by vasopressin was significantly less in the group with an increased concentration of calcium in media than the control group, but phosphodiesterase activity was not affected by calcium concentration in the media. These data suggest that the impaired urinary concentrating ability in hypercalcemic kidneys is due at least in part to the direct inhibitory effect of calcium on the vasopressin-dependent cyclic AMP system at the level of adenylate cyclase in renal medulla.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=301652Documentos Relacionados
- ON THE MECHANISM OF IMPAIRMENT OF RENAL CONCENTRATING ABILITY IN HYPERCALCEMIA*
- ON THE IMPAIRMENT OF RENAL CONCENTRATING ABILITY IN PROLONGED HYPERCALCEMIA AND HYPERCALCIURIA IN MAN*
- Urinary concentrating ability in early experimental pyelonephritis
- ON THE MECHANISM OF IMPAIRMENT OF RENAL CONCENTRATING ABILITY IN POTASSIUM DEFICIENCY*
- Urinary cyclic AMP analyzed as a function of the serum calcium and parathyroid hormone in the idfferential diagnosis of hypercalcemia.
