ANTIDIURETIC HORMONE IN BRONCHOGENIC CARCINOMA

Abstract

Immunoactive antidiuretic hormone (ADH) was measured by radioimmunoassay in the plasma, lung tumors and metastatic tumors of 19 patients with bronchogenic carcinoma. Ten patients had hyponatremia and carcinoma of the small oat cell type. Plasma ADH measured in 9 of these patients ranged from 11-270 pg/ml and was elevated above the normal range (4.6-6.2 pg/ml) in all subjects. ADH-immunoreactive material was detectable in all primary lung tumors (range 9-1080 pg/mg wet wt, n = 7) and metastases (range 5-63 pg/mg wet wt, n = 9) obtained from the hyponatremic patients. A statistical relationship existed between plasma and tumor ADH concentration in 6 patients where both measurements were performed. Three patients had small cell carcinomas (2 oat cell and 1 anaplastic) without overt hyponatremia. ADH-like material was detectable in the lung tumors (18 and 1.1 pg/mg wet wt) and liver metastases (4 and 1.0 pg/mg wet wt) of 2 patients but not in the 3rd. Of the remaining patients 4 had squamous cell carcinomas and 2 had adenocarcinomas. None had hyponatremia. ADH-like material was undetectable in all lung tumors, metastatic tumors and uninvolved tissue from these patients. ADH extracted from the pituitaries of 4 patients ranged from 6400-13200 pg/mg wet wt. ADH immunoreactive extracts of 6 lung tumors and 9 metastases (all oat cell) showed the same pattern on elution from a Sephadex G-25 column. A large peak which made up 65% of the total activity was eluted in the same position as synthetic arginine vasopressin and contained comparable amounts of immunoreactive and bioactive ADH. Two smaller peaks (8 and 27% of total activity) were eluted in positions of higher MW and contained more immunoreactive than bioactive ADH. In contrast, 3 of 4 pituitary extracts showed only a single peak which eluted in the same position as marker vasopressin.