title: Renal denervation enhances the phosphaturic effect of parathyroid hormone.
abstract: Hyperventilation/hypocapnia increases renal phosphate reabsorption and decreases the phosphaturic effect of parathyroid hormone (PTH). Recent studies suggest that the blunted phosphaturic effect of PTH in hyperventilated/hypocapnic rats may be mediated by the stimulation of renal beta-adrenoreceptors. In the present study, no differences in plasma catecholamine levels were detected in hyperventilated/hypocapnic rats as compared to hyperventilated/normocapnic rats. Therefore, studies were performed to determine the role of the renal nerves in the blunted phosphaturic effect of PTH in hyperventilated/hypocapnic rats. In clearance experiments in acutely thyroparathyroidectomized male Sprague-Dawley rats, PTH infusion increased the fractional excretion of phosphate (FEPi) in the denervated left kidney of hyperventilated/hypocapnic rats (n = 8), from 2.4 +/- 1.1 to 18.6 +/- 2.7%, as compared to 1.0 +/- 0.3 to 9.1 +/- 2.1% in the contralateral innervated kidney. Denervation of the left kidney in hyperventilated/normocapnic rats (n = 8) also significantly increased the phosphaturic response to PTH by 2.5 +/- 1.5 to 26.9 +/- 3.0% as compared to 0.9 +/- 0.5 to 18.6 +/- 2.6% in the contralateral innervated kidney. The phosphaturic responses to PTH were similar when comparing the denervated kidney in hyperventilated/hypocapnic rats with the innervated kidney of hyperventilated/normocapnic rats. Thus, renal denervation enhanced the phosphaturic effect of PTH in both hyperventilated/hypocapnic and hyperventilated/normocapnic rats. These results suggest that renal nerves play a role in the modulation of the phosphaturic effect of PTH.
authors.affiliation: Department of Physiology, Mayo Clinic and Foundation, Rochester, Minn.
authors.forename: K J
authors.initials: KJ
authors.lastname: Mann
authors.forename: A
authors.initials: A
authors.lastname: Rybczynska
authors.forename: T J
authors.initials: TJ
authors.lastname: Berndt
authors.forename: A
authors.initials: A
authors.lastname: Hoppe
authors.forename: G M
authors.initials: GM
authors.lastname: Tyce
authors.forename: F G
authors.initials: FG
authors.lastname: Knox
mesh_terms: D000818:Animals; D003714:Denervation; D006935:Hypercapnia / Q000652:urine; D006985:Hyperventilation / Q000652:urine; D007668:Kidney / Q000294:innervation*; D008297:Male; D010281:Parathyroid Hormone / Q000494:pharmacology*; D010710:Phosphates / Q000652:urine*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D010281:Parathyroid Hormone; D010710:Phosphates