Antidiuretic hormone in bronchogenic carcinoma

Area of Science:

• Endocrinology
• Oncology
• Pulmonology

Background:

• Hyponatremia is a common complication in patients with bronchogenic carcinoma, particularly small cell lung cancer.
• Antidiuretic hormone (ADH), also known as arginine vasopressin, plays a crucial role in water balance.
• Ectopic hormone production by tumors can lead to various paraneoplastic syndromes.

Purpose of the Study:

• To measure immunoactive antidiuretic hormone (ADH) levels in the plasma, primary lung tumors, and metastatic tumors of patients with bronchogenic carcinoma.
• To investigate the relationship between plasma ADH levels and tumor ADH content.
• To characterize the immunoreactive and bioactive forms of ADH in tumor extracts.

Main Methods:

• Radioimmunoassay was used to measure ADH in plasma and tumor tissues.
• Tumor extracts were analyzed using Sephadex G-25 column chromatography.
• Bioactivity of ADH was assessed in conjunction with immunoreactivity.

Main Results:

• Elevated plasma ADH levels were observed in all patients with hyponatremia and small cell lung cancer.
• ADH-immunoreactive material was detected in primary lung tumors and metastases of hyponatremic patients.
• Tumor extracts from small cell lung cancer contained both immunoreactive and bioactive ADH, with a significant portion eluting similarly to synthetic arginine vasopressin.

Conclusions:

• Small cell lung cancer, particularly in patients with hyponatremia, can ectopically produce and secrete antidiuretic hormone (ADH).
• Tumor-derived ADH appears to be biologically active, contributing to the observed hyponatremia.
• The presence of ADH in tumor tissue supports the hypothesis of ectopic hormone production in bronchogenic carcinoma.