Absence of Seasonal Variation in Serum Concentrations of 1,25-Dihydroxyvitamin D Despite a Rise in 25-Hydroxyvitamin D in Summer*

1. The serum concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were measured in 44 patients with primary hyperparathyroidism. 2. In 14 patients the serum concentration of 1,25-dihydroxyvitamin D was greater than normal (142–337 pmol/l). One patient had a subnormal concentration of 1,25-dihydroxyvitamin D (36 pmol/l) but no other evidence of vitamin D deficiency. 3. The possible biological determinants of the serum concentration of 1,25-dihydroxyvitamin D were sought by multivariate analysis of relevant variables. The serum concentration of 1,25-dihydroxyvitamin D was found to be significantly and positively correlated with the serum concentrations of 25-hydroxyvitamin D (P < 0.001) and parathyroid hormone (P < 0.003), and with the glomerular filtration rate (P < 0.03), and negatively correlated with the serum concentrations of calcium (P < 0.02) and phosphate (P = 0.055) (multiple R = 0.638,P < 0.002). 4. In primary hyperparathyroidism the major determinant of serum 1,25-dihydroxyvitamin D is the availability of precursor 25-hydroxyvitamin D. 5. The finding that serum 1,25-dihydroxyvitamin D is commonly normal in patients with primary hyperparathyroidism despite an adequate state of vitamin D nutrition, can be explained in terms of the constraining influences of hypercalcaemia and variable degrees of renal dysfunction on the biosynthesis of 1,25-dihydroxyvitamin D.

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Influence of physical mobility and season on 25-hydroxyvitamin D-parathyroid hormone interaction and bone remodelling in the elderly

Acta Endocrinologica ◽

10.1530/eje.0.1430673 ◽

2000 ◽

pp. 673-679 ◽

Cited By ~ 21

Author(s):

R Theiler ◽

HB Stahelin ◽

M Kranzlin ◽

G Somorjai ◽

L Singer-Lindpaintner ◽

...

Keyword(s):

Vitamin D ◽

The Elderly ◽

Serum Concentrations ◽

Institutionalized Elderly ◽

Hydroxyvitamin D ◽

Dihydroxyvitamin D ◽

1,25 Dihydroxyvitamin D ◽

Physical Mobility ◽

25 Hydroxyvitamin D ◽

Mobility Status

OBJECTIVE: To investigate influences of physical mobility and season on 25-hydroxyvitamin D-intact parathyroid hormone (iPTH) interaction in the elderly. DESIGN: We examined 188 frail institutionalized elderly at the expected nadir of their serum vitamin D concentrations (winter). This group was compared with 309 healthy ambulatory elderly at the expected time of maximum vitamin D repletion (summer), to accentuate the influences of season and physical activity. METHODS: Serum concentrations of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, iPTH and urinary deoxypyridinoline (DPD) were measured. RESULTS: Vitamin D metabolites were significantly lower in the institutionalized elderly (P<0.0001), with an 82.5% prevalence of vitamin D deficiency (25-hydroxyvitamin D <12ng/ml) in institutionalized elderly in wintertime and 15.5% in ambulatory elderly in summertime. Overall, median iPTH did not differ between groups. However, median iPTH secretion in the presence of low vitamin D serum concentrations (5-30ng/ml) was greater in ambulatory elderly. This could be explained by lower mobility status being correlated with greater serum calcium concentrations (r=0.24, P=0.02 in women; r=0.35, P=0. 001 in men) and greater urinary excretion of DPD (r=0.41, P=0.0001 in women; r=0.42, P=0.0002 in men), independent of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D and iPTH. CONCLUSIONS: These data support the hypothesis that immobility, even in the presence of vitamin D deficiency, acts as an overriding influence on bone metabolism by promoting bone resorption (measured as urinary DPD) and increasing serum calcium independent of iPTH. Therefore mobility status may substantially affect 25-hydroxyvitamin D threshold values and the degree to which patients benefit from vitamin supplementation.

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Changes in serum 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D and 1,25-dihydroxyvitamin D in response to three vitamin D3 supplementation regimens

Endocrine Abstracts ◽

10.1530/endoabs.44.p72 ◽

2016 ◽

Author(s):

Jonathan Tang ◽

Holly Nicholls ◽

John Dutton ◽

Isabelle Piec ◽

Christopher Washbourne ◽

...

Keyword(s):

Vitamin D3 ◽

Hydroxyvitamin D ◽

Dihydroxyvitamin D ◽

1,25 Dihydroxyvitamin D ◽

Vitamin D3 Supplementation ◽

25 Hydroxyvitamin D

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Immunopurified 25-hydroxyvitamin D 1 alpha-hydroxylase and 1,25-dihydroxyvitamin D 24-hydroxylase are closely related but distinct enzymes.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)50758-x ◽

1992 ◽

Vol 267 (5) ◽

pp. 3498-3505 ◽

Cited By ~ 1

Author(s):

M Burgos-Trinidad ◽

R Ismail ◽

R.A. Ettinger ◽

J.M. Prahl ◽

H.F. DeLuca

Keyword(s):

Hydroxyvitamin D ◽

Dihydroxyvitamin D ◽

1,25 Dihydroxyvitamin D ◽

25 Hydroxyvitamin D

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Bone marrow and serum concentrations of 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1.ALPHA.,25-dihydroxyvitamin D in patients with leukemia and normal subjects.

Journal of Nutritional Science and Vitaminology ◽

10.3177/jnsv.35.211 ◽

1989 ◽

Vol 35 (4) ◽

pp. 211-223 ◽

Cited By ~ 3

Author(s):

Sonoko MASUDA ◽

Toshio OKANO ◽

Kyoko NOMA ◽

Mika HAMASAKI ◽

Tadashi KOBAYASHI ◽

...

Keyword(s):

Bone Marrow ◽

Normal Subjects ◽

Serum Concentrations ◽

Hydroxyvitamin D ◽

Dihydroxyvitamin D ◽

25 Hydroxyvitamin D

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The interrelationship of serum 1,25-dihydroxyvitamin D, 25-hydroxyvitamin D and 24,25-dihydroxyvitamin D in pregnancy at term: a meta-analysis

HORMONES ◽

10.14310/horm.2002.1263 ◽

2010 ◽

Vol 9 (2) ◽

pp. 136-144 ◽

Cited By ~ 37

Author(s):

Peter Papapetrou

Keyword(s):

Meta Analysis ◽

Hydroxyvitamin D ◽

Dihydroxyvitamin D ◽

1,25 Dihydroxyvitamin D ◽

25 Hydroxyvitamin D ◽

In Pregnancy

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An international comparison of vitamin D metabolite measurements.

Clinical Chemistry ◽

10.1093/clinchem/30.3.399 ◽

1984 ◽

Vol 30 (3) ◽

pp. 399-403 ◽

Cited By ~ 51

Author(s):

M J Jongen ◽

F C Van Ginkel ◽

W J van der Vijgh ◽

S Kuiper ◽

J C Netelenbos ◽

...

Keyword(s):

Reference Sample ◽

Plasma Samples ◽

Internal Reference ◽

Hydroxyvitamin D ◽

Dihydroxyvitamin D ◽

1,25 Dihydroxyvitamin D ◽

Three Samples ◽

25 Hydroxyvitamin D ◽

Laboratory Survey ◽

Standard Solutions

Abstract An international 19-laboratory survey was organized to compare assays for 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D in plasma. Each participant received two ethanolic standard solutions of each metabolite and eight plasma samples. Each laboratory used its usual procedures. Mean interlaboratory coefficients of variation (CVs) for the eight plasma samples were 35%, 43%, and 52% for 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1,25-dihydroxyvitamin D, respectively. Average CVs for the standard solutions were 27%, 23%, and 25%, respectively. Of the eight plasma samples, five had the same concentration for one of the metabolites. One sample was diluted to 0.6 times its original concentration and three samples were fortified with one or more of the metabolites under investigation. Fourteen of 18 laboratories (78%) could distinguish between the five unchanged samples and the modified ones with their 25-hydroxyvitamin D assay. Nine of 12 (75%) could distinguish the modified samples from the other samples with the 24,25-dihydroxyvitamin D assay. Only eight of 15 (53%) could do this their 1,25-dihydroxyvitamin D assay. Values from different laboratories evidently cannot be intercompared without making an actual comparison of the assay procedures. Furthermore, in case of clinical applications of these assays, each laboratory should establish its own reference values and should continually use an internal reference sample to assess the precision of the procedures.

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