Format

Send to

Choose Destination
Calcif Tissue Int. 1997 Aug;61(2):101-3.

Increased serum 1,25-dihydroxyvitamin D after growth hormone administration is not parathyroid hormone-mediated.

Author information

1
Department of Pediatrics, Medical University of Charleston, Charleston, South Carolina 29425, USA.

Abstract

To assess the effects of growth hormone (GH) on serum 1,25-dihydroxyvitamin D [1,25(OH)2D], we performed the following prospective crossover study in six healthy, young, adult, white men. During each of two admissions for 2 1/2 days to a general clinical research center, subjects were placed on a daily dietary calcium intake of 400 mg. Serum calcium, phosphorus, 1,25(OH)2D, immunoreactive intact parathyroid hormone (PTH), insulin-like growth factor I (IGF-I), IGF binding protein 3 (IGFBP3), tubular reabsorption of phosphate (TMP/GFR) were measured. Recombinant human GH (rhGH, Humatrope) (25 microg/kg/day subcutaneously for 1 week) was administered prior to and during one of the admissions. Results are expressed as mean +/- SEM. Whereas serum 1,25(OH)2D (58.9 +/- 7.7 versus 51.6 +/- 7.4 pg/ml, P< 0.01), serum phosphorus (4.5 +/- 0.1 versus 3.7 +/- 0.1 mg/dl, P < 0.01), TRP (92.0 +/- 0.5 versus 87.8 +/- 0.7 mg/dl, P < 0.005), TMP/GFR (4.6 +/- 0.1 versus 3.5 +/- 0.2, P < 0.005), and urinary calcium (602 +/- 49 versus 346 +/- 25 mg/day, P < 0.001) increased significantly, serum PTH decreased significantly (19.9 +/- 1.9 versus 26.8 +/- 4.0 pg/ml, P < 0.05) and serum calcium did not change when subjects received rhGH. These findings indicate that in humans, GH affects serum 1,25(oh)2D independently of circulating PTH and that this effect is mediated by IGF-I. We propose, therefore, that one potential mechanism by which GH stimulates increases in bone mass is via modest increases in serum 1,25(OH)2D.

PMID:
9312396
[Indexed for MEDLINE]

Supplemental Content

Loading ...
Support Center