title: Peripheral effects of PTH are not altered after thyroid surgery in euthyroid patients.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Surgery, Lund University Hospital, Lund, Sweden. Pia.Lindblom@kir.lu.se
authors.forename: P
authors.initials: P
authors.lastname: Lindblom
authors.forename: A
authors.initials: A
authors.lastname: Isaksson
authors.forename: J
authors.initials: J
authors.lastname: Westerdahl
authors.forename: A
authors.initials: A
authors.lastname: Bergenfelz
mesh_terms: D000328:Adult; D000368:Aged; D001769:Blood / Q000378:metabolism; D002118:Calcium / Q000097:blood / Q000652:urine; D005260:Female; D006801:Humans; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology*; D010710:Phosphates / Q000652:urine; D011184:Postoperative Period; D013961:Thyroid Gland / Q000601:surgery*; D014556:Urine / Q000737:chemistry; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D010281:Parathyroid Hormone; D010446:Peptide Fragments; D010710:Phosphates; D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D; D002118:Calcium