scholarly journals Older Age Is Associated with Decreased Levels of VDR, CYP27B1, and CYP24A1 and Increased Levels of PTH in Human Parathyroid Glands

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Yi Jiang ◽  
Liyan Liao ◽  
Jina Li ◽  
Larry Wang ◽  
Zhongjian Xie
Keyword(s):  
Parathyroid Hormone ◽  
Inverse Correlation ◽  
Serum Levels ◽  
Older Age ◽  
Parathyroid Glands ◽  
Expression Levels ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
25 Hydroxyvitamin D

Parathyroid glands contain the vitamin D receptor (VDR) and 25-hydroxyvitamin D-1α-hydroxylase (CYP27B1) and 24-hydroxylase (CYP24A1), which catalyze the production and degradation of 1,25-dihydroxyvitamin D [1,25(OH)2D], respectively. Previous studies have shown that the serum level of intact parathyroid hormone (iPTH) increases with age. We hypothesized that the expression of CYP27B1 or VDR in parathyroid glands decreases with age, which might account for the increased serum levels of iPTH due to decreased suppression of parathyroid hormone (PTH) secretion by 1,25(OH)2D in older people. To test this hypothesis, we examined relative expression levels of VDR, CYP27B1, CYP24A1, and PTH in specimens from parathyroid glands unintentionally removed during thyroidectomy for 70 patients varying in age from 10 to 70 years. The results showed that there was an inverse correlation between age and VDR, CYP27B1, and CYP24A1 expression (p<0.05). A significant positive correlation between PTH expression levels and age was also observed (p<0.05). These data indicate that older age is associated with decreased levels of VDR, CYP27B1, and CYP24A1 and increased levels of PTH in human parathyroid glands.

Vitamin D and Calcitonin Treatment in Patients with Femoral Neck Fracture: A Prospective Controlled Clinical Study

1989 ◽  
Vol 17 (3) ◽  
pp. 226-242 ◽  
Author(s):  
E. Harju ◽  
R. Punnonen ◽  
R. Tuimala ◽  
J. Salmi ◽  
I. Paronen
Keyword(s):  
Vitamin D ◽  
Parathyroid Hormone ◽  
Serum Levels ◽  
Serum Calcitonin ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Age Related ◽  
Neck Fracture ◽  
25 Hydroxyvitamin D

The effects on general and bone metabolism of femoral neck fracture patients of 0.25 μg α-calcoid given orally twice daily ( n=9) and 25 μg calcitonin given subcutaneously 30 times ( n=10) in 10 weeks were studied against a control ( n=ll). Bone histology and histomorphometry showed non-age related osteoporosis in 30% and osteomalacia in 22% of the patients studied. Impaired serum vitamin D status was found in 47 – 88% of patients, secondary hyperparathyroidism and increased serum parathyroid hormone in 59% and decreased serum calcitonin levels in 69%. On histology, normal findings and non-age related osteoporosis on histology were associated with low serum levels of 25-hydroxyvitamin D3,1,25- and 24,25-dihydroxy vitamin D3. Very high serum levels of 1,25-dihydroxyvitamin D3 and low levels of 25-hydroxyvitamin D3 occurred in fracture patients with osteomalacia. Calcitonin improved calcium balance, reduced osteoporosis and increased the serum 1,25- and 24,25-dihydroxyvitamin D3 levels but had no effect on osteomalacia. Vitamin D reduced osteomalacia, slightly increased the serum 1,25-dihydroxyvitamin D3 concentration and decreased serum levels of parathyroid hormone. Both treatments gave a similar slight decrease in serum calcitonin concentrations. A mechanism of action for the treatments is suggested.

Parathyroidectomy abolishes the increase of renal 25-hydroxyvitamin D-1 alpha-hydroxylase in lactating rats

1993 ◽  
Vol 264 (6) ◽  
pp. E981-E985 ◽  
Author(s):  
B. Lobaugh ◽  
S. C. Garner ◽  
J. A. Lovdal ◽  
A. Boass ◽  
S. U. Toverud
Keyword(s):  
Elevated Serum ◽  
Inorganic Phosphorus ◽  
Parathyroid Glands ◽  
Female Rats ◽  
Curvilinear Relationship ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
25 Hydroxyvitamin D ◽  
Serum Ionized Calcium

Serum ionized calcium (Ca), but not inorganic phosphorus or immunoreactive parathyroid hormone, negatively correlates with renal 25-hydroxyvitamin D-1 alpha-hydroxylase (1 alpha-hydroxylase) and serum 1,25-dihydroxyvitamin D in intact lactating rats. The present study tested the hypothesis that the presumed stimulation of renal 1 alpha-hydroxylase by hypocalcemia requires the presence of intact parathyroid glands. Lactating and nonlactating rats were surgically parathyroidectomized (PTX) or sham-operated (sham) at 9-10 days of lactation. Later (24 h) the rats were bled, nephrectomized, and killed. In lactating PTX rats, serum ionized Ca decreased to 50% of the level of sham rats, and serum 1,25-dihydroxyvitamin D fell to 37 +/- 5.0 pg/ml compared with 82 +/- 13.0 pg/ml for sham lactating rats but was still 2.5 times the value for nonlactating PTX rats (15 +/- 0.8 pg/ml). In contrast to the still elevated serum 1,25-dihydroxyvitamin D concentration in lactating PTX rats, renal 1 alpha-hydroxylase was suppressed to the same low level as in nonlactating PTX rats, suggesting the existence of extrarenal synthesis of 1,25-dihydroxyvitamin D in lactation. A curvilinear relationship was revealed between serum ionized Ca and renal 1 alpha-hydroxylase in sham lactating and nonlactating rats (r2 = 0.71, P < 0.0001). However, in PTX rats, decreasing ionized Ca did not lead to any increase in 1 alpha-hydroxylase above the low baseline values seen at ionized Ca concentrations between 1.3 and 1.5 mM. We therefore conclude that intact parathyroid glands are required for hypocalcemia to activate renal 1 alpha-hydroxylase in female rats.

Effect of Parathyroid Hormone on cAMP and 1,25-Dihydroxyvitamin D Formation and Renal Handling of Phosphate in Vitamin D-Dependent Rickets

PEDIATRICS ◽  
1983 ◽  
Vol 71 (1) ◽  
pp. 59-63
Author(s):  
Dagfinn Aarskog ◽  
Lage Aksnes ◽  
Trond Markestad
Keyword(s):  
Vitamin D ◽  
Parathyroid Hormone ◽  
Serum Concentration ◽  
Urinary Excretion ◽  
Serum Levels ◽  
Renal Handling ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Control Subjects

Studies were carried out to compare the effects of parathyroid extract (PTE) on the serum concentration of 1,25-dihydroxyvitamin D (1,25[OH]2D), 24,25-dihydroxyvitamin D (24,25[OH]2D), 25,26-dihydroxy vitamin D (25,26[OH]2D) and cAMP, and the urinary excretion of calcium, phosphorus, and cAMP in two normal adult subjects, and in a girl with vitamin D-dependent rickets. The concentration of 1,25[OH]2D was markedly decreased even when she was receiving a daily dose of 25,000 IU of ergocalciferol. PTE infusion resulted in a prompt and distinct increase in the serum levels and the urinary excretion of cAMP in the patient and control subjects. In the control subjects the serum concentration of 1,25[OH]2D increased after the PTE infusion, whereas there was no response in the patient with vitamin D-dependent rickets. The two other dihydroxylated metabolites of vitamin D showed no consistent response to the PTE infusion in the control subjects or the patient. The patient showed no phosphaturic response to PTE while she was receiving high-dosage ergocalciferol treatment. By contrast, when the patient was re-studied after therapy with lα-hydroxyvitamin D, PTE infusion resulted in an increase in urinary phosphate excretion. These findings might lend support for the notion that 1,25[OH]2D has an effect on tubular phosphate resorption and has a permissive role in the phosphaturic effect of parathyroid hormone. The present findings also confirm that the formation of 1,25[OH]2D is impaired in vitamin D-dependent rickets and indicate that the renal 25-hydroxyvitamin D-lα-hydroxylase is unresponsive to the stimulatory effect of parathyroid hormone in this condition.

scholarly journals Association of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D and parathyroid hormone with mortality among middle-aged and older European men

2013 ◽  
Vol 43 (4) ◽  
pp. 528-535 ◽  
Author(s):  
David M. Lee ◽  
Dirk Vanderschueren ◽  
Steven Boonen ◽  
Terence W. O'Neill ◽  
Neil Pendleton ◽  
...  
Keyword(s):  
Parathyroid Hormone ◽  
Middle Aged ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
25 Hydroxyvitamin D

Calcium, Vitamin D and Parathyroid Hormone Relationships in Pregnant Caucasian and Asian Women and Their Neonates

1987 ◽  
Vol 24 (1) ◽  
pp. 22-28 ◽  
Author(s):  
F Okonofua ◽  
R K Menon ◽  
S Houlder ◽  
M Thomas ◽  
D Robinson ◽  
...  
Keyword(s):  
Vitamin D ◽  
Parathyroid Hormone ◽  
Inverse Correlation ◽  
Plasma Calcium ◽  
Asian Women ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
The Face ◽  
25 Hydroxyvitamin D ◽  
Caucasian Women

Plasma calcium, serum 25 hydroxyvitamin D [25(OH)D], 1,25 dihydroxyvitamin D[1,25(OH)2D] and parathyroid hormone (PTH) have been measured in pregnant and newborn Caucasians and Asians. Calcium and 25(OH)D concentrations were lower in Caucasian than in Asian women at all four stages (three trimesters and during labour) of pregnancy. PTH concentrations were greater in Asian than in Caucasian women during the three trimesters, but not at labour, and increased in both groups through pregnancy, without a concomitant change in plasma calcium concentrations. There was a significant inverse correlation between calcium and PTH, as well as 25(OH)D and PTH, concentrations. These data demonstrate the presence of progressive ‘hyperparathyroidism’ during pregnancy in Caucasian and Asian women. The higher PTH concentrations in Asian women may reflect the necessity of maintaining adequate plasma calcium concentrations through PTH-induced osteolysis in the face of vitamin D deficiency. Relative hyperparathyroidism in Asians may contribute to net loss of calcium from the skeleton and osteopenia in Asian women. Calcium, 25(OH)D and l,25(OH)2D concentrations were lower, and those of PTH higher, in Asian newborns compared with Caucasian newborns. Serum 1,25(OH)2D concentrations in the Asian newborn, though lower than respective maternal levels, were comparable with normal adult levels, indicating that 1,25(OH)2D biosynthesis is stimulated in the Asian newborn to compensate for the low serum 25(OH)D concentrations.

scholarly journals Hypercalcemia due to sun exposure in a patient with multiple myeloma and elevated parathyroid hormone-related protein

2003 ◽  
pp. 351-355 ◽  
Author(s):  
PD Papapetrou ◽  
M Bergi-Stamatelou ◽  
H Karga ◽  
S Thanou
Keyword(s):  
Multiple Myeloma ◽  
Parathyroid Hormone ◽  
Sun Exposure ◽  
High Serum ◽  
Related Protein ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Parathyroid Hormone Related Protein ◽  
25 Hydroxyvitamin D

A patient with multiple myeloma who developed hypercalcemia during three different stages of his disease, with a different hypercalcemic agent elevated in his serum on each occasion, is described. The initial episode of hypercalcemia was associated with high serum interleukin-6 (IL-6). After treatment for myeloma normocalcemia was achieved. Subsequently, a relapse of hypercalcemia occurred, this time characterized by frankly elevated plasma parathyroid hormone-related protein (PTHrP) but normal IL-6. Monotherapy with pamidronate infusions resulted in remission of the hypercalcemia and a significant fall in PTHrP levels. A third spell of hypercalcemia characterized by an acute rise in serum 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D to abnormally high levels occurred during the summer season after prolonged and intense exposure to the sun.

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