A pilot study on hypothalamo-pituitary-adrenocortical axis in primary hyperparathyroidism.
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Date
2009-10
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Abstract
Background & objectives: Parathormone (PTH) and calcium, both have been shown to stimulate adrenal
steroidogenesis in animal models and in vitro experiments. This is attributed to structural similarity
between 15-25 amino acid region of the parathyroid hormone (PTH) and 1-11 amino acid region of
adrenocorticotropin (ACTH). However, there are no in vivo human data regarding the effect of PTHcalcium
axis on adrenocortical function.
Materials: Ten patients with primary hyperparathyroidism underwent evaluation for cortisol dynamics
including 0800 h and 2000 h plasma cortisol on day 1, cortisol response to insulin induced hypoglycaemia
(IIH) on day 2, and 1 mg overnight dexamethasone suppression test (ONDST) on day 4. Serum aldosterone
was also measured at 0800 h in fasting state on salt ad libitum for three days. These parameters were
repeated 3 months after curative parathyroidectomy.
Results: Basal plasma cortisol level at 0800 h and 2000 h were within upper normal range and loss of
circadian rhythm in cortisol secretion was observed in half and forty per cent of patients had nonsuppressibility
with ONDST. The defined peak cortisol response to insulin induced hypoglycaemia (>550
nmol/l) was achieved in all and nearly one third of patients had exaggerated response (>2000 nmol/l). After
curative parathyroidectomy, the abnormalities in circadian rhythm and non-suppressibility with ONDST
continued to prevail in 40 per cent of patients. The peak cortisol response to IIH showed a decrement but
remained higher than normal. No correlation was observed between circulating parathyroid hormone
and calcium with cortisol levels. Serum aldosterone was in upper normal range pre - and postoperatively,
though it decreased postoperatively, but it could not attain a statistical significance (p = 0.5).
Interpretation & conclusion: Abnormalities in hypothalamo-pituitary-adrenocortical axis in primary
hyperparathyroidism do occur, however these are inconsistent and do not recover in majority of patients even after 3 months of curative parathyroidectomy.
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Keywords
cortisol, hyperparathyroidism, osteoporosis
Citation
Rajput Rajesh, Bhansali Anil, Bhadada Sanjay Kumar, Behera Arunanshu, Mittal B R, Sialy Ravinder, Khandelwal N. A pilot study on hypothalamo-pituitary-adrenocortical axis in primary hyperparathyroidism. Indian Journal of Medical Research. 2009 Oct; 130(4): 418-422.