Continuous cell lines have been established from a variety of biopsy and postmortem species of tumor from patients with small-cell carcinoma of the lung (SCCL) and have been maintained over several years. The medium from the cultures has been assayed for peptide, glycoprotein, and steroid hormones. Significant amounts of 14 hormones including calcitonin, adrenocorticotropin (ACTH), parathormone, luteinizing hormone, chorionic gonadotropin, glucagon, growth hormone, somatostatin, prolactin, p-endorpin, lipotropin, oxytocin-neurophysin, vasopressin-neurophysin, and estradiol have been demonstrated. Up to ten different hormones have been produced by a single cell line. Most produce ACTH and all evaluated so far produce estradiol. These studies indicate that cells from SCCL have a potential for producing a wide variety of hormones and that this characteristic can be maintained for prolonged periods of culture in v i m. Cancer 47:1289-1296, 1981. VIDENCE OF HORMONE production by nonE endocrine tumors has attracted increasing interest from a biologic as well as a clinical perspective, as indicated in recent reviews.9~28~36,37,47~5z~57 M any varieties of tumors have been associated with the ectopic production of one or more hormones, although small-cell or oat-cell carcinoma of the lung (SCCL) is best known for this characteristic.2 Atlhough paraneoplastic syndromes may be clinically recognizable in approximately 25% of patients,13 other studies have shown that abnormal levels of hormones such as ACTH, vasopressin (VP), or calcitonin (CT) may be seen in up to over 50% of patients.50 More recently, North et al. 42 have identified elevated levels of both vasopressin-and oxytocin-associated neurophysins in 60% of patients with small-cell carcinoma of the lung. A series of cultures from SCCL has been estab-l i ~ h e d ~ ~. ~ ~ and hormone production in v i m has been evaluated. A brief preliminary survey of some of these data has been presented p r e v i o ~ s l y. ~ ~ The relationship of in v i m production to clinical manifestations in patients from whom the tumor cells were obtained has also been considered in this paper. From the Departments of *Pathology and tMedicine, Dart-mouth-Hitchcock Medical Center, Hanover, New Hampshire. Materials and Methods Tumor cell cultures have been established and maintained in Falcon flasks with RPMI 1640 with 20% fetal calf serum (FCS) or Waymouth MB752/1 with 20% FCS. Flasks were incubated at 37 C in 5% CO, and air. Cultures have been subcultured at weekly to monthly intervals as needed either by mechanieal dissociation or with 0.25% trypsin and/or 0.02% EDTA in calcium and magnesium-free Hanks balanced salt solution. Subcul-tures were initiated at lo6 cells/ml. Details concerning the establishment of these cultures and their characteristics have been previously d e ~ c r i b e d. ~ ~ ? ~ ~ In the experiments in which hormones were assayed, cultures were grown until relatively heavy; at that time the medium was replaced. Four days later, the medium was collected and frozen until assa...