Extrahypothalamic Brain Luteinizing Hormone:Characterization by Radioimmunoassay, Chromatography, Radioligand Assay and Bioassay

Abstract
Luteinizing hormone (LH) is present in the hypothalamus of rats. It has chromatographic and biologic characteristics similar to pituitary LH. This report focuses on extrahypothalamic LH that is widely distributed in the rodent CNS. This material has a chromatographic profile similar to that of pituitary LH. Serial dilution of this material is parallel with dilutions of rat pituitary LH in the immunoassay. Brain extracts are active in the testis LH radioligand receptor assay and in the rat interstitial cell testosterone secretion bioassay. Prior incubation of extract with LH antibody significantly attenuates both of these activities. Thus, extrahypothalamic LH has immunologic, chromatographic, and biologic characteristics similar to hypothalamic and pituitary LH.