Serum parathyroid hormone

Many of the adverse effects of lithium can be ascribed to the action of lithium on adenylate cyclase, the key enz)nne that links many hormones and neurotransmitters with their intracellular actions. Thus antidiuretic hormone and thyroid-stimulating-hormone-sensitive adenylate cyclases are inhibited by therapeutic concentrations of the drug, which frequently leads to enhanced diuresis, h)rpoth)n oidism and even goitre. Aldosterone synthesis is increased following chronic lithium treatment and is probably a secondary consequence of the enhanced diuresis caused by the inhibition of antidiuretic-hormone-sensitive adenylate cyclase in the kidney. There is also evidence that chronic lithium treatment causes an increase in serum parathyroid hormone levels and, with this, a rise in calcium and magnesium concentrations. A decrease in plasma phosphate and in bone mineralization can also be attributed to the effects of the drug on parathyroid activity. Whether these changes are of any clinical consequence is unclear. 

Serum parathyroid hormone should be obtained at least once between the 1st 2 wk to 3 mo of treatment... 

E544 Manimekalai, S., Unni, S., Sundaram, G.S. and Goldstein, P.J. (1989). Serum parathyroid hormone in hemodialysis patients. Clin. Chem. 35,1140, Abstr. 349. 

Davis OK, Hawkins DS, Rubin LP, Posillico JT, Brown EM, Schiff I. Serum parathyroid hormone in pregnant women determined by an immunoradiometric assay for intact PTH. J Clin Endocrinol Metab 1988 67 850-2. 

Qi Q, Monier-Faugere MC> Geng Z, MaHuche HH. Predictive value of serum parathyroid hormone levels for bone turnover in patients on chronic maintenance dialysis. Am J Kidney Dis 1995 26 622-31,... 

Sethi R, Kukreja SC, Bowser EN, Hargis GK, Henderson WJ, Williams GA, Effect of meal on serum parathyroid hormone and calcitonin possible role... 

Metabolic bone disease is a complication usually reported in adults and children receiving long-term home PN. This disorder in adults is characterized by osteomalacia with or without osteoporosis that may present without associated chnical, radiologic, or biochemical abnormalities. The diagnosis may not be made in premature infants until after the development of bone fractures or overt rickets. The etiology is poorly understood and likely multifactorial. Treatment options include pharmacologic intervention, calcimn and vitamin D supplementation, and exercise. Others have recommended removal of vitamin D from the PN in patients with low serum parathyroid hormone and 1,25-hydroxyvitamin D concentrations. ... 

No histopathologic changes were observed in the adrenal, pancreas, pituitary, or parathyroid glands of male or female rats that were fed Aroclor 1016, 1242,1254, or 1260 for 24 months at dose levels of 8.0-11.2,4.0-5.7,4.3-6.1, or 4.1-5.8 mg/kg/day, respectively (Mayes et al. 1998). Serum parathyroid hormone levels were not affected in rats treated with up to 25 mg/kg/day Aroclor 1254 for up to 15 weeks (Andrews 1989). 

After successful parathyroidectomy, serum parathyroid hormone levels... 

Fio. 12. Scheme of calcium and phosphorus homeostasis in progressive renal disease — , increases decreases GFR, glomerular filtration rate P, serum phosphorus Ca2+, serum ionized calcium Ca, calcium 1,25-DHCC, 1,25-dihydroxy cholecalciferol PTH, serum parathyroid hormone Cp, phosphate clearance. 

Clarkson. E.M., Luck, V.A., Hynson, W.V., et al. (1972). The effect of aluminium hydroxide on calcium, phosphorus and aluminium balances, the serum parathyroid hormone concentration and the aluminium content of bone in patients with chronic renal failure. Clin. Sci., 43, 519-531. 

A 38-year-old man with acute promyelocytic leukemia who was taking itraconazole 200 mg bd was given all-trans retinoic acid and during the third course of maintenance therapy developed acute renal insufficiency and symptomatic hypercalcemia, which was treated with high-volume crystalloid infusions and furosemide. Renal function was restored, and the serum calcium concentration returned to normal within 4 days after withdrawal of ATRA. The peak serum calcium concentration was 3.67 mmoUl. Serum parathyroid hormone was undetectable, and there were no increases in the concentrations of prostaglandins or vitamin D metabolites. Hypercalcemia recurred during a fourth course of ATRA. 

Dawson-Hughes B, Harris SS, and Dallal GE (1997) Plasma calcidiol, season, and serum parathyroid hormone concentrations in healthy elderly men and women. American Journal of Clinical Nutrition 65 65-71. 

---