Procollagen type 1 C-terminal extension peptide serum levels following parathyroidectomy in hyperparathyroid patients.
Procollagen type 1 is mainly synthesized by osteoblasts and, after cleavage of the N- and C-terminal extension peptides, is utilized for collagen fibril deposition in the osteoid tissue. Serum levels of C-terminal extension peptide (Pcoll-1-C) of the procollagen molecule has been considered a useful marker for the evaluation of the rate of osteoblastic procollagen synthesis. To appraise whether in vivo parathyroid hormone (PTH) plays a suppressive role in the synthesis of procollagen type 1, a study has been carried out in 16 patients, 10 with severe secondary hyperparathyroidism of chronic renal failure and 6 with primary hyperparathyroidism. Following parathyroidectomy (PTX), in chronic renal failure patients a 94% fall in serum intact iPTH and a decline of serum calcium to hypocalcemic levels requiring calcitriol administration were observed. Serum Pcoll-1-C increased markedly with a peak after 7 days and a subsequent decline. Similar changes were observed for alkaline phosphatase and osteocalcin. In primary hyperparathyroidism, PTX was followed by an 88% drop in iPTH and mild hypocalcemia not requiring calcitriol administration. Also in this group serum Pcoll-1-C increased significantly with the same time course, unaccompanied by changes in alkaline phosphatase and osteocalcin. In 4 unsuccessfully neck-operated control patients no change in serum Pcoll-1-C levels was recorded during a period of 2 weeks postoperatively. In conclusion, acute withholding of parathyroid hypersecretion is accompanied by an abrupt and transitory increase of serum Pcoll-1-C, not dependent on calcitriol administration. Hypocalcemia following PTX may in part be due to uncoupling of bone formation and resorption.
Coen
G
G
Chair of Nephrology, 3rd Surgical Clinic, La Sapienza University, Rome, Italy.
Mazzaferro
S
S
De Antoni
E
E
Chicca
S
S
DiSanza
P
P
Onorato
L
L
Spurio
A
A
Sardella
D
D
Trombetta
M
M
Manni
M
M
D000328:Adult; D000368:Aged; D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers / Q000097:blood; D002117:Calcitriol / Q000008:administration & dosage; D002908:Chronic Disease; D005260:Female; D006801:Humans; D006961:Hyperparathyroidism / Q000097:blood* / Q000209:etiology / Q000601:surgery; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000209:etiology / Q000601:surgery; D007676:Kidney Failure, Chronic / Q000097:blood / Q000150:complications; D008297:Male; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood / Q000187:drug effects; D010281:Parathyroid Hormone / Q000097:blood*; D016105:Parathyroidectomy; D010446:Peptide Fragments / Q000096:biosynthesis / Q000097:blood*; D011182:Postoperative Care; D011300:Preoperative Care; D011347:Procollagen / Q000096:biosynthesis / Q000097:blood*; D012720:Severity of Illness Index
D015415:Biomarkers; D010281:Parathyroid Hormone; D010446:Peptide Fragments; D011347:Procollagen; C042813:procollagen type I carboxy terminal peptide; D015675:Osteocalcin; D000469:Alkaline Phosphatase; D002117:Calcitriol