Effect of parathyroid hormone on 1,25-dihydroxyvitamin D formation in type I pseudohypoparathyroidism.

Abstract

The role of parathyroid hormone (PTH) and cAMP in the hydroxylation of 25-hydroxyvitamin D to 1,25-dihydroxyvitamin D [1,25-(OH)2D] was explored in two young male volunteers and a patient with pseudohypoparathyroidism type I. Parathyroid extract infusion resulted in a prompt and distinct increase in the plasma levels of cAMP and the urinary excretion of the nucleotide in the normal controls, whereas there was only a negligible increase in the patient. In both the patient and the control subjects, the serum concentration of 1,25-(OH)2D showed a distinct increase after the parathyroid extract infusion. The responses were similar in magnitude and were apparent after 2 h, with a further rise 4 h in the patient and one of the controls, whereas the other control subject only responded after 4 h. The findings are consistent with the assumption that a normal renal cAMP response to PTH is not essential for the PTH stimulation of the renal 25-hydroxyvitamin D-1 alpha-hydroxylase. The two other dihydroxymetabolites of vitamin D, 24,25-(OH)2D and 25,26-(OH)2D, showed no consistent response to the PTH infusion in either the controls or the patient.

• Authors: L Aksnes, D Aarskog
• Journal: The Journal of clinical endocrinology and metabolism (J Clin Endocrinol Metab) Vol. 51 Issue 6 Pg. 1223-6 (Dec 1980) ISSN: 0021-972X [Print] United States
• PMID: 6255001 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Dihydroxycholecalciferols
• Hydroxycholecalciferols
• Parathyroid Hormone
• Phosphates
• Cyclic AMP
• Calcitriol
• Calcium

Topics

• Adult
• Calcitriol
• Calcium (urine)
• Cyclic AMP (blood, urine)
• Dihydroxycholecalciferols (blood)
• Humans
• Hydroxycholecalciferols (blood)
• Kinetics
• Male
• Parathyroid Hormone (blood)
• Phosphates (urine)
• Pseudohypoparathyroidism (metabolism)