PTH and calcitonln are the two major hormones controlling calcium metabolism. Recently two new substances related to these hormones have been Isolated: calcitonln gene related peptide (CGRP) and PTH‐related protein (PTHrP). CGRP Is a potent vasodilator and stimulant of intestinal secretion while PTHrP Is probably the agent responsible for humoral hypercalcaemla of malignancy. We report here a patient with a prostatlc tumour presenting with vasodilatlon, diarrhoea and hypercalcaemia. Our investigations revealed that the primary prostatic and liver secondary tumour contained CGRP, calcitonln and PTHrP. Most of the immunoreactive CGRP in the tumour and plasma co‐eluted with the biologically active form of CGRP. The circulating levels of CGRP correlated with the presence of the diarrhoea. PTHrP concentration In the tumours was one of the highest reported for any tumour although previous studies may have utilized less than optimal extraction procedures. The somatostatin analogue, octreotide (SMS 201–995), did not reduce the plasma CGRP or the diarrhoea, a finding similar to that seen in patients with medullary thyroid carcinoma and high plasma CGRP. The hypercalcaemla was also unaffected by octreotide administration. This is the first report of a prostatic tumour associated with over‐production of calcltonin, PTHrP and CGRP. The major life‐threatening effects of this unusual case of prostatic carcinoma were diarrhoea and hypercalcaemia. Both these effects could be tentatively ascribed to newly discovered substances, CGRP and PTHrP. With the greater availability of assays to measure CGRP and PTHrP in plasma, a detailed examination of the incidence of over‐production of these substances In various cancers will be possible.
|Number of pages||7|
|Publication status||Published - 1 Jan 1991|