Urinary and nephrogenous cyclic AMP and renal phosphate handling in normal subjects and patients with parathyroid dysfunction

Abstract. Studies were performed in 60 patients with proven primary hyperparathyroidism pre-operatively and in 54 of these patients post-operatively, 22 patients with permanent hypoparathyroidism and 34 normal subjects. Urinary and nephrogenous cyclic AMP excretion were increased in the hyperparathyroid patients with an overlap of values with the normal group of 10 and 9%, respectively. Values fell in all patients post-operatively, and were decreased in those with permanent hypoparathyroidism. TmPO4/GFR was decreased in the preoperative hyperparathyroid patients and rose postoperatively while it was increased in the hypoparathyroid patients with an overlap of values with the normal group of 9%. Post-operative hypocalcaemia due to bone hunger was associated with continuing normo- or hypophosphataemia and urinary cyclic AMP that exceeded 4.5 nm/dl GF while those who developed permanent hypoparathyroidism had hyperphosphataemia, increased TmPO4/GFR and urinary cyclic AMP that was less than 3.5 nM/dl G.F. Urinary and nephrogenous cyclic AMP were equally effective in characterizing patients with primary hyperparathyroidism and less effective in distinguishing patients with hypoparathyroidism from normal while TmPO4/GFR estimates were more effective in delineating the hypoparathyroid state.

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Control of Renal Tubular Phosphate Reabsorption by Parathyroid Hormone in Man

Clinical Science ◽

10.1042/cs0530431 ◽

1977 ◽

Vol 53 (5) ◽

pp. 431-438

Author(s):

D. A. Walker ◽

S. Joyce Davies ◽

K. Siddle ◽

J. S. Woodhead

Keyword(s):

Vitamin D ◽

Parathyroid Hormone ◽

Cyclic Amp ◽

Primary Hyperparathyroidism ◽

Normal Subjects ◽

Vitamin D Metabolism ◽

Phosphate Reabsorption ◽

Important Regulator ◽

Urinary Cyclic Amp ◽

Renal Tubular

1. The maximum tubular reabsorption capacity for phosphate relative to glomerular filtration rate (Tm,P/GFR) was found to range from 0·8 to 1·5 mmol/l in 32 normal fasting subjects. In 14 patients with primary hyperparathyroidism and five patients with hyperparathyroidism secondary to vitamin D deficiency or malabsorption values ranged from 0·2 to 0·8 mmol/l. 2. Plasma parathyroid hormone concentrations measured by an immunoradiometric technique ranged from <0·15 to 0·9 ng/ml in the normal subjects and from 0·5 to 10 ng/ml in the patients with hyperparathyroidism. There was no correlation, however, between plasma parathyroid hormone and Tm,P/GFR in either normal or abnormal groups. 3. Plasma parathyroid hormone was lower in 11 out of 13 patients with primary hyperparathyroidism 3 or 4 weeks after tumour removal than immediately before the operation. In all cases there was a rise in Tm,P/GFR, though not all values were normalized. 4. Changes in plasma parathyroid hormone, Tm,P/GFR and plasma and urinary cyclic AMP concentrations were measured during infusion of bovine parathyroid hormone into normal fasting subjects. Phosphate reabsorption fell markedly in response to low doses of parathyroid hormone (0·5 i.u. h−1 kg−1), higher doses (4 i.u. h−1 kg−1) producing little additional change in Tm,P/GFR despite large changes in cyclic AMP excretion. At the highest doses used (8 i.u. h−1 kg−1) apparent saturation of the renal adenylate cyclase occurred. During an infusion of hormone, 0·25 i.u. h−1 kg−1 over 3 h, a fall in Tm,P/GFR was recorded at concentrations of immunoreactive parathyroid hormone within the normal range for endogeneous hormone. At such concentrations it was not possible to detect significant changes in either plasma or urine cyclic AMP. 5. It is concluded that parathyroid hormone is an important regulator of renal phosphate handling under normal physiological conditions. Such a regulatory process has been implicated in the control of vitamin D metabolism.

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Serum ionized calcium, nephrogenous and total urinary cyclic AMP and urinary phosphate in normal subjects

Scandinavian Journal of Clinical and Laboratory Investigation ◽

10.3109/00365518409161391 ◽

1984 ◽

Vol 44 (2) ◽

pp. 111-118 ◽

Cited By ~ 7

Author(s):

J. Thode ◽

S. Nistrup Holmegaard ◽

O. Siggaard Andersen

Keyword(s):

Cyclic Amp ◽

Normal Subjects ◽

Ionized Calcium ◽

Urinary Cyclic Amp ◽

Serum Ionized Calcium

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Urinary Adenosine Cyclic 3′,5′-Monophosphate in Idiopathic Calcium Stone-Formers: Response to An Oral Calcium Load

Clinical Science ◽

10.1042/cs0660193 ◽

1984 ◽

Vol 66 (2) ◽

pp. 193-199 ◽

Cited By ~ 5

Author(s):

V. R. Walker ◽

R. A. L. Sutton

Keyword(s):

Cyclic Amp ◽

Excretion Rate ◽

Normal Subjects ◽

Oral Calcium ◽

Calcium Stone ◽

Stone Formers ◽

Glomerular Filtrate ◽

Calcium Load ◽

Urinary Cyclic Amp ◽

Lower Urinary

1. Idiopathic calcium stone-formers with hypercalciuria during fasting have significantly lower urinary cyclic AMP levels (nmol/dl of glomerular filtrate) than fasting normocalciuric stone-formers. 2. Female subjects, including both normal subjects and idiopathic calcium stone-formers, have higher urinary cyclic AMP levels than their male counterparts, and this difference is significant when urinary cyclic AMP is expressed in the units μmol/g of creatinine. Expressing urinary cyclic AMP in nmol/dl of glomerular filtrate reduces this difference but does not abolish it. Thus, in comparing urinary cyclic AMP levels in various subgroups of the calcium stone-formers and in normal subjects, both sex differences and the units of urinary cyclic AMP expression must be taken into consideration. 3. The magnitude of the change in urinary cyclic AMP in response to an oral calcium load appears to depend on the antecedent urinary cyclic AMP excretion rate, whereby those individuals (either normal subjects or calcium stone-formers) having the highest urinary cyclic AMP levels demonstrate the greatest fall in urinary cyclic AMP after a calcium load.

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