Expression of parathyroid hormone related peptide in human pituitary tumours

The presence of parathyroid hormone related peptide (PTHrP) was studied in 20 patients with pituitary adenomas and one patient with pituitary adenocarcinoma. PTHrP expression was shown in almost all of the pituitary adenomas (95%) and in 100% (n = 7) growth hormone producing pituitary adenomas. A metastatic lesion from a pituitary growth hormone producing adenocarcinoma revealed strongly expressed PTHrP. It was weakly detected in normal pituitary cells in all of the specimens (n = 10). There was no significant correlation, however, between PTHrP expression and the clinical or pathological features of growth hormone producing tumours. Apart from an important role in the physiological function of the pituitary gland, PTHrP may be closely related to somatotroph tumorigenicity.