Immunological evidence for the occurrence of luteinizing hormone-releasing factor and the alpha-subunit of glycoprotein hormones in carcinoid tumors.

The immunoperoxidase technique was used to identify LRF and glycoprotein hormones or their subunits in 22 carcinoid tumors of various origins. All tumors were positive for both LRF and the alpha-subunit, whereas stainings with antisera against the beta-subunits of CG, LH, FSH, and TSH were negative. The binding of LRF and the alpha-subunit within the same malignant tissue raises the possibility of a functional relationship between the two.