Plasma levels of parathyroid hormone-related peptide are elevated in hyperprolactinemia and correlated to bone density status.
Osteopenia is an important clinical manifestation of hyperprolactinemia. Bone loss in these patients has mainly been attributed to concomitant deficiency of gonadal hormones rather than to hyperprolactinemia per se. Parathyroid hormone-related peptide (PTHrP) is expressed in human mammary tissue, and elevated circulating PTHrP levels as well as concomitant hypercalcemia have been described during lactation. We sought to determine circulating PTHrP levels in patients with long-standing hyperprolactinemia and whether PTHrP may exert possible systemic effects on bone and mineral metabolism. We studied 45 patients (30 women and 15 men) with persisting hyperprolactinemia 6 +/- 4 years (mean +/- SD) after trans-sphenoidal surgery for prolactin-producing pituitary adenomas. PTHrP levels in 117 healthy controls were 10.6 +/- 7.3 pmol-eq/l (mean +/- SD). In hyperprolactinemic patients, plasma PTHrP was elevated to 30.3 +/- 13.4 pmol-eq/l (p < 0.001, n = 45), and in patients with humoral hypercalcemia of malignancy PTHrP levels were 52.9 +/- 29.6 (p < 0.001 to controls and hyperprolactinemic patients). Fifty-three percent of hyperprolactinemic patients (n = 24) had clearly elevated PTHrP levels (> 2 SD). Retrospective immunocytochemical studies of the removed pituitary adenomas from 19 patients generally showed a higher degree of immunoreactivity for PTHrP (1-34) in all but one case when compared with normal pituitary tissue. Patients with elevated circulating PTHrP levels showed in most instances strong immunoreactivity to PTHrP in 70-100% of tumor cells.(ABSTRACT TRUNCATED AT 250 WORDS)
Stiegler
C
C
Department of Internal Medicine, Karl Franzens University, Graz, Austria.
Leb
G
G
Kleinert
R
R
Warnkross
H
H
Ramschak-Schwarzer
S
S
Lipp
R
R
Clarici
G
G
Krejs
G J
GJ
Dobnig
H
H
D015502:Absorptiometry, Photon; D000236:Adenoma / Q000473:pathology / Q000601:surgery; D000328:Adult; D000704:Analysis of Variance; D001794:Blood Pressure / Q000502:physiology; D001798:Blood Proteins / Q000378:metabolism; D015519:Bone Density / Q000502:physiology*; D001851:Bone Diseases, Metabolic / Q000503:physiopathology; D002118:Calcium / Q000097:blood / Q000652:urine; D005260:Female; D006801:Humans; D006966:Hyperprolactinemia / Q000097:blood / Q000503:physiopathology*; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis / Q000097:blood; D010281:Parathyroid Hormone / Q000097:blood*; D044162:Parathyroid Hormone-Related Protein; D010758:Phosphorus / Q000652:urine; D010902:Pituitary Gland / Q000378:metabolism; D010911:Pituitary Neoplasms / Q000473:pathology / Q000601:surgery; D011506:Proteins / Q000032:analysis / Q000378:metabolism*; D012189:Retrospective Studies
D001798:Blood Proteins; D009363:Neoplasm Proteins; C470121:PTHLH protein, human; D010281:Parathyroid Hormone; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins; D010758:Phosphorus; D002118:Calcium