Effects of serum calcium and phosphorus on skeletal mineralization in vitamin D-deficient rats

1986 ◽  
Vol 251 (2) ◽  
pp. E234-E240 ◽  
Author(s):  
M. E. Holtrop ◽  
K. A. Cox ◽  
D. L. Carnes ◽  
M. F. Holick
Keyword(s):  
Vitamin D ◽  
Serum Calcium ◽  
Volume Density ◽  
Normal Serum ◽  
Serum Phosphorus ◽  
Deficient Diet ◽  
Hydroxyvitamin D ◽  
Normal Serum Calcium ◽  
Calcium And Phosphorus ◽  
Low Serum

In the present study, we have evaluated the role of calcium and phosphorus concentrations in serum on the mineralization of bone in the absence of vitamin D. This was accomplished by feeding mother rats and subsequently their pups vitamin D-deficient diets varying in calcium, phosphorus, and lactose content. After 5-7 wk on these diets, serum concentrations of 25-hydroxyvitamin D [25(OH)D] and 1,25-hydroxyvitamin D [1,25(OH)2D] were undetectable. Rats fed a vitamin D-deficient diet containing 0.44% calcium and 0.3% phosphorus showed a serum calcium of 4.9-5.9 mg/dl and a serum phosphorus of 7.3-8.2 mg/dl; rickets (wide epiphysial plates) had developed as well as osteomalacia (wide osteoid seams). Rats maintained on a vitamin D-deficient diet containing 3% calcium and 0.65% phosphorus had normal serum calcium, low serum phosphorus, and severe rickets, but osteomalacia was not seen. Rats fed a diet containing 20% lactose, 4% calcium, and 1% phosphorus showed normal serum calcium, somewhat low serum phosphorus, normal serum PTH, normal width of the epiphysial plate, normal volume density of trabecular bone, and normal volume density of osteoid seams. These data confirm the findings of others, using a different experimental model, that serum calcium and phosphorus concentrations are the determining factors in mineralization defects and not the absence of 25(OH)D or 1,25(OH)2D. In these rats thyroparathyroidectomy is well tolerated, which makes for an ideal model for the study of the effects of calcium-regulating hormones on bone histology, cytology, and biochemistry.

IDIOPATHIC HYPERCALCEMIA

PEDIATRICS ◽  
1959 ◽  
Vol 24 (2) ◽  
pp. 258-269
Author(s):  
David W. Smith ◽  
Robert M. Blizzard ◽  
Harold E. Harrison
Keyword(s):  
Vitamin D ◽  
Serum Calcium ◽  
Normal Serum ◽  
Early Infancy ◽  
Serum Assay ◽  
Supplemental Vitamin ◽  
Normal Serum Calcium

A case of idiopathic hypercalcemia present from early infancy and diagnosed at 5 years of age is reported in which the serum assay of vitamin D indicated elevated levels. After discontinuation of supplemental vitamin D and a diet low in calcium the concentrations of calcium and vitamin D in the serum gradually returned to normal over a period of 18 months. Roentgenograms of the bones showed evidence of demineralization rather than increased density as reported in other cases of "idiopathic" hypercalcemia. During a subsequent 2-year follow-up the patient has maintained a normal serum calcium. The etiology is discussed with particular reference to the role of vitamin D in this case

Responses of serum calcium and phosphorus in the frog Rana tigrina to injection of various vitamin D analogs

1987 ◽  
Vol 65 (8) ◽  
pp. 2111-2112 ◽  
Author(s):  
Ajai K. Srivastav ◽  
L. Rani ◽  
K. Swarup
Keyword(s):  
Vitamin D ◽  
Serum Calcium ◽  
Vitamin D Analogs ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Rana Tigrina ◽  
Calcium Deposits ◽  
25 Hydroxyvitamin D ◽  
Calcium And Phosphorus

Intraperitoneal injections of either vitamin D3 (4 IU/100 g body wt.), 25 hydroxyvitamin D3 (100 ng/100 g body wt.), or 1,25 dihydroxyvitamin D3 (100 ng/100 g body wt.) for 15 days induced hypercalcemia, hyperphosphatemia, and depletion of calcium deposits in the paravertebral lime sacs in an anuran, Rana tigrina.

Study of Vitamin D Status among Postmenopausal Women

2017 ◽  
Vol 5 (1) ◽  
pp. 28-34
Author(s):  
Nithya P Jayakumar ◽  
Bharathi Rao ◽  
Nikil Shetty
Keyword(s):  
Vitamin D ◽  
Dietary Intake ◽  
Vitamin D Deficiency ◽  
Postmenopausal Women ◽  
Serum Calcium ◽  
Sun Exposure ◽  
Serum Phosphorus ◽  
Vitamin D Status ◽  
Medical College ◽  
Calcium And Phosphorus

ABSTRACT Aims To evaluate vitamin D, serum calcium, and serum phosphorus levels in postmenopausal women attending gynecology outpatient department in Lady Goschen and Kasturba Medical College Attavar hospitals. Objective To study the prevalence of vitamin D deficiency among the studied group. To correlate vitamin D levels with diet and environmental factors. Materials and methods The study was conducted in 100 postmenopausal women attending Lady Goschen hospital and Kasturba Medical College Attavar hospital, Mangaluru. It was a hospital-based, prospective cross-sectional study conducted over the period between August 2014 and June 2016. Levels of vitamin D and serum calcium and phosphorus were assessed in them. Results A total of 11% were found to have vitamin D deficiency, 38 and 48% had insufficient levels and sufficient levels of vitamin D respectively, 53% had normal levels of serum calcium, and 47% had inadequate levels. About 70% were found to have normal levels of serum phosphorus and 24% had inadequate levels. Dietary intake was found to be inadequate in 61% of the studied population. Serum calcium and phosphorus deficiency had significant corelation with vitamin D deficiency. Also significant corelation was noted with sun exposure and dietary intake in relation to vitamin D. No corelation was established between hypertension, diabetes and vitamin D. Conclusion This study helped us to assess basal levels of vitamin D, serum calcium, and serum phosphorus among postmenopausal women, giving us an idea regarding prevalence of vitamin D deficiency among South Indian postmenopausal women. We should consider counseling all postmenopausal patients regarding the benefit of vitamin D supplementation, adequate dietary intake, and sun exposure. How to cite this article Jayakumar NP, Rao B, Shetty N. Study of Vitamin D Status among Postmenopausal Women. J South Asian Feder Menopause Soc 2017;5(1):28-34.

scholarly journals Vitamin D deficiency in rats with normal serum calcium concentrations.

1982 ◽  
Vol 79 (15) ◽  
pp. 4791-4794 ◽  
Author(s):  
G. E. Lester ◽  
C. J. VanderWiel ◽  
T. K. Gray ◽  
R. V. Talmage
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Serum Calcium ◽  
Normal Serum ◽  
Normal Serum Calcium

Rickets and Metabolic Disorders

PEDIATRICS ◽  
1990 ◽  
Vol 85 (4) ◽  
pp. 625-625
Author(s):  
STUART C. MORRISON ◽  
DOUGLAS S. KERR
Keyword(s):  
Alkaline Phosphatase ◽  
Serum Calcium ◽  
Metabolic Disorders ◽  
Normal Serum ◽  
X Rays ◽  
Elevated Alkaline Phosphatase ◽  
Normal Serum Calcium ◽  
Metabolic Data ◽  
Calcium And Phosphorus

In Reply.— We have reviewed the letter from Drs Ozsoylu and Besim and have reviewed the metabolic data from our patient with tyrosinosis to determine if there was evidence of rickets in our patient. At the time that the published x-rays were obtained, the patient had normal serum calcium and phosphorus. However, a month earlier, when the x-rays appeared normal apart from probable osteopenia, the patient did have persistent hypophosphatemia, 1.5 to 1.8 mg/dL (normal 4.0 to 6.0 mg/dL), and elevated alkaline phosphatase, 956 IU/L (normal 50 to 380 IU/L).

Deletion of the vitamin D receptor specifically in the parathyroid demonstrates a limited role for the receptor in parathyroid physiology

2009 ◽  
Vol 297 (5) ◽  
pp. F1192-F1198 ◽  
Author(s):  
Tomer Meir ◽  
Ronen Levi ◽  
Liesbet Lieben ◽  
Steven Libutti ◽  
Geert Carmeliet ◽  
...  
Keyword(s):  
Vitamin D ◽  
Serum Calcium ◽  
Vitamin D Receptor ◽  
Normal Serum ◽  
Calcium Receptor ◽  
Collagen Crosslinks ◽  
Limited Role ◽  
Normal Serum Calcium ◽  
Total Body ◽  
Serum Pth

1,25(OH)2D3 decreases parathyroid hormone (PTH) gene transcription through the vitamin D receptor (VDR). Total body VDR−/− mice have high PTH levels, hypocalcemia, hypophosphatemia, and bone malformations. To investigate PTH regulation by the VDR specifically in the parathyroid, we generated parathyroid-specific VDR knockout mice ( PT-VDR−/−). In both strains, there was a decrease in parathyroid calcium receptor (CaR) levels. The number of proliferating parathyroid cells was increased in the VDR−/− mice but not in the PT-VDR−/− mice. Serum PTH levels were moderately but significantly increased in the PT-VDR−/− mice with normal serum calcium levels. The sensitivity of the parathyroid glands of the PT-VDR−/− mice to calcium was intact as measured by serum PTH levels after changes in serum calcium. This indicates that the reduced CaR in the PT-VDR−/− mice enables a physiologic response to serum calcium. Serum C-terminal collagen crosslinks, a marker of bone resorption, were increased in the PT-VDR−/− mice with no change in the bone formation marker, serum osteocalcin, consistent with a resorptive effect due to the increased serum PTH levels in the PT-VDR−/− mice. Therefore, deletion of the VDR specifically in the parathyroid decreases parathyroid CaR expression and only moderately increases basal PTH levels, suggesting that the VDR has a limited role in parathyroid physiology.

Metabolism of 1,25-dihydroxyvitamin D3

1984 ◽  
Vol 64 (2) ◽  
pp. 478-504 ◽  
Author(s):  
R. Kumar
Keyword(s):  
Parathyroid Hormone ◽  
Serum Calcium ◽  
Biliary Excretion ◽  
Extracellular Fluid ◽  
Serum Phosphorus ◽  
General Terms ◽  
Wide Range ◽  
Calcium Phosphorus ◽  
Calcium And Phosphorus ◽  
Low Serum

Synthesis of 1,25(OH)2D3 is controlled by numerous factors. The major ones, however, are the circulating amounts of parathyroid hormone (the secretion of which is stimulated by low serum calcium), serum or extracellular fluid phosphorus concentrations, circulating levels of 1,25(OH)2D3 itself, and perhaps serum calcium directly. Many of the other factors noted have effects in vitro only or effects that are observed inconsistently or in one species only. Thus, in low-calcium states, 1,25(OH)2D3 synthesis increases because of increased parathyroid hormone activity. Parathyroid hormone may stimulate 1,25(OH)2D3 synthesis directly or via alterations (a decrease) in serum phosphorus or both. Low serum phosphorus will stimulate 1,25(OH)2D3 synthesis independent of parathyroid hormone levels. Low serum calcium may directly stimulate 25(OH)D3 1 alpha-hydroxylase activity independently of parathyroid hormone. In general terms the vitamin D-endocrine system tends to correct abnormalities in calcium and phosphorus homeostasis. The further metabolism of 1,25(OH)2D3 to other metabolites appears to be mainly a degradative or excretory process. Currently there is no evidence that 1,25(OH)2D3 must itself be altered to other metabolites prior to inducing intestinal calcium transport or bone mobilization. The processes involved in the excretion of 1,25(OH)2D3, such as side-chain oxidation and biliary excretion, are not regulated by serum calcium, phosphorus, or 1,25(OH)2D3 levels. The biliary excretion pathway is also unsaturable over a very wide range and not regulated by calcium, phosphorus, or vitamin D3. Therefore these processes, which account for a large part of the metabolism of 1,25(OH)2D3, are largely unregulated by factors that control the synthesis of 1,25(OH)2D3 and regulate the formation of other calcium-controlling hormones. Other processes involved in the metabolism of 1,25(OH)2D3, such as 24-hydroxylation and 26-hydroxylation, occur in normocalcemic and normophosphatemic states. 24-Hydroxylation is also induced by 1,25(OH)2D3, which benefits the organism, because excessive 1,25(OH)2D3 in various tissues can be altered to a less active metabolite, 1,24,25(OH)3D3. Although there is still no evidence concerning the regulation of C-24 oxidation by dietary calcium and phosphorus levels, the fact that this process is induced by 1,25(OH)2D3 suggests that the metabolic pathway functions in much the same manner as the 24-hydroxylation pathway. The formation of 1,25(OH)2D3-26,23-lactone occurs in normocalcemic states and in situations in which 1,25(OH)2D3 has been administered.

Is Intact PTH a Sensitive Biochemical Indicator of Deranged Calcium Homeostasis in Vitamin D Deficiency?

1989 ◽  
Vol 26 (4) ◽  
pp. 324-327 ◽  
Author(s):  
J P Ashby ◽  
D J Newman ◽  
M G Rinsler
Keyword(s):  
Vitamin D ◽  
Vitamin D Deficiency ◽  
Calcium Homeostasis ◽  
Biochemical Parameters ◽  
Normal Serum ◽  
Intact Pth ◽  
Hydroxyvitamin D ◽  
Biochemical Indicator ◽  
Normal Serum Calcium ◽  
25 Hydroxyvitamin D

Intact PTH was elevated in 38/40 Asians with reduced serum 25 hydroxyvitamin D [25(OH)D] including seven patients with normal serum calcium, phosphate and alkaline phosphatase. Changes in intact PTH were disproportionately greater than for other biochemical parameters, making it the most sensitive early indicator of deranged calcium homeostasis in vitamin D deficiency.

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