Parathyroid Function in Spontaneous Primary Hypothyroidism

Adams, Philip C.; Chalmers, T. M.; Riggs, B. Lawrence; Jones, James D.

doi:10.1677/joe.0.0400467

Cited by 15 publications

(4 citation statements)

References 15 publications

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“…It has previously been shown that the responsiveness to PTH is reduced and the exchangeable calcium pool is decreased during hypothyroidism [21][22][23][24]. In the present study the serum concentration of free T 4 decreased, and TSH showed a compensatory discrete increase 1 year after hemithyroidectomy.…”

Section: Discussionsupporting

confidence: 59%

Hemithyroidectomy: Long‐term effects on parathyroid function—preliminary report

2001

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Early hypocalcemia after thyroid surgery has frequently been reported, whereas data regarding long-term effects on calcium homeostasis are scarce. We have previously studied patients after hemithyroidectomy with an oral calcium load test and found normal parathyroid hormone (PTH) suppression. However, the 1,25-dihydroxyvitamin D concentration was decreased and the phosphate concentration increased, implying parathyroid insufficiency. We therefore proceeded to investigate PTH secretion and suppression in 10 euthyroid patients subjected to hemithyroidectomy due to benign thyroid disease before and at 1 year after surgery. In addition, biochemical variables known to influence calcium homeostasis were analyzed. Basal, maximal, and total PTH secretion were unaltered 1 year postoperatively. However, maximal PTH secretion was reached at a lower serum level of ionized calcium, and there was a tendency toward increased parathyroid sensitivity to ionized calcium. Furthermore, compared to preoperative, total serum calcium, 1,25-dihydroxyvitamin D, and free thyroxine (T4) concentrations were decreased at follow-up. Total serum calcium and 1,25-dihydoxyvitamin D concentrations were decreased 1 year after hemithyroidectomy. These changes were not due to parathyroid insufficiency. Instead, our results imply increased parathyroid sensitivity to calcium and possibly reduced peripheral sensitivity to PTH.

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Section: Discussionsupporting

confidence: 59%

Hemithyroidectomy: Long‐term effects on parathyroid function—preliminary report

2001

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“…The target cells of iPTH are less responsive to the iPTH in hypothyroid cases, which also aggravates the vitamin D deficiency in the hypothyroid cases. 22 This study shows the decreased levels of vitamin D in females than males, but it was not significant. The other studies have also mentioned the nonsignificant decrease in vitamin D levels among males and females.…”

Section: Discussionmentioning

confidence: 52%

Reliable Earlier and Causative Biomarker in newly Diagnosed Hypothyroid Cases—Vitamin D: A Case–control Study

Prabha¹

2017

Indian Journal of Medical Biochemistry

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diagnosis of hypothyroidism and in the therapeutic aspect also. Vitamin D, being a hormone, acts on various types of cells and plays multiple roles. Other than bone metabolism, it has a causative role in various diseases 2,3 like diabetes mellitus, 4 cancer, 5 multiple sclerosis, 6 autoimmune diseases, 7 and atherosclerosis. 8 Vitamin D not only acts through the immune-mediated process but also acts on the thyroid follicular cells by inhibiting directly the thyrotropin-mediated stimulation of iodine uptake in dose-dependent manner. 9 A population-based study has observed low thyroid-stimulating hormone (TSH) among younger individuals. 10 Hence, the reliability of TSH in the diagnosis of hypothyroidism in younger individuals is affected. Thus, in the present study, the relation between TSH and vitamin D with triiodothyronine (T3) and thyroxine (T4) at the time of diagnosis of hypothyroid cases has been evaluated. MATERIALS AND METHODSTwo hundred cases of newly diagnosed hypothyroidism and 200 healthy individuals as controls were included in this case-control study. Written consent was taken from all the participants in the study. Complete history was taken. They belonged to the age group of 15 to 30 years. None of the participants were started on treatment for hypothyroidism. Patients with renal diseases, hepatic disease, rheumatologic disease, diabetes mellitus, alcoholics, dermatologic diseases, and child birth in last 1 year were excluded from the study. Control groups of people were those who visited the hospital for health checkup and the volunteers of blood donations. Venous samples were collected after 12 hours of fasting in plain tubes. For all the participants of the study, plasma glucose (glucose oxidase and peroxidase method), serum creatinine (modified Jaffe's kinetic method), and blood urea (urease method) were evaluated to rule out the basic pathology and it was done in Beckman Coulter AU 480.

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“…However, it has also been suggested that thyroid hormones can modulate the peripheral response to PTH. In overt hypothyroidism, reduced serum levels of calcium [11, 12]and increased serum levels of PTH [13, 14, 15, 16]have been reported. Despite higher PTH values, other indices of PTH activity have been found to be reduced [16].…”

Section: Discussionmentioning

confidence: 99%

Peripheral Effects of PTH Are Not Altered after Thyroid Surgery in Euthyroid Patients

Lindblom¹,

Isaksson

Westerdahl³

et al. 2001

Horm Res Paediatr

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Background: We have previously found decreased serum levels of both ionized calcium and 1,25(OH)₂D and an increase in serum phosphate levels at 1 year after hemithyroidectomy. However, basal and stimulated parathyroid hormone (PTH) secretions were not altered. To investigate whether the observed biochemical changes after unilateral thyroid surgery may be due to a relative end-organ resistance to PTH, we studied the peripheral effects of infused hPTH-(1–34) in 6 patients preoperatively and 3 months after hemithyroidectomy. Methods: Serum levels of TSH, FT₄ and FT₃ were measured pre- and postoperatively. hPTH-(1–34) was infused at 0.9 IU/kg/h during 6 h. Blood samples for analysis of ionized calcium, intact PTH, phosphate, 25(OH)D, 1,25(OH)₂D and urinary samples for calcium, phosphate and nephrogenous(n)-cAMP analysis were taken at baseline, when the infusion was discontinued after 6 h and at 24 h. Results: Three months after hemithyroidectomy, serum levels of FT₃ were decreased and TSH levels increased. Pre- and postoperative hPTH-(1–34) infusions induced increased serum levels of ionized calcium, 1,25(OH)₂D, increased urinary excretion of phosphate and elevated n-cAMP levels. The changes in the studied biochemical variables during the hPTH-(1–34) infusions did not differ between the two study occasions. Conclusion: By using a 6-hour hPTH-(1–34) infusion protocol, we have shown that the peripheral PTH effect is not altered by a slight reduction in thyroid hormone levels at 3 months after hemithyroidectomy.

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Parathyroid Function in Spontaneous Primary Hypothyroidism

Cited by 15 publications

References 15 publications

Hemithyroidectomy: Long‐term effects on parathyroid function—preliminary report

Hemithyroidectomy: Long‐term effects on parathyroid function—preliminary report

Reliable Earlier and Causative Biomarker in newly Diagnosed Hypothyroid Cases—Vitamin D: A Case–control Study

Peripheral Effects of PTH Are Not Altered after Thyroid Surgery in Euthyroid Patients

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