Soluble Luteinizing Hormone/Human Chorionic Gonadotropin Receptors of the Rat Ovary: Comparative Studies of Water- and Detergent-Soluble Receptors*

The water-soluble LH-hCG receptors of the luteinized rat ovary have the properties of glycoproteins and can be separated into four fractions by chromatography on Sepharose-Concanavalin A. Polyacrylamide gel electrophoresis of these fractions demonstrates a broad similarity of molecular compositions. However, the chromatographic fractions had different quantities of the individual receptor species (mol wt, 165,000, 81,000, 24,000, 48,000, and 12,000). While all receptor species declined in the desensitized ovaries the losses of the 24.000 and 12,000 mol wt species were most prominent. Analysis of detergent extracts demonstrated that water-soluble and detergent-soluble LH/hCG receptors have comparable molecular compositions and resolved similarly during chromatography on Sepharose-Concanavalin A. These results have also indicated that lectin affinity chromatography is a powerful tool for the initial purification step of water-soluble or detergent-extracted ovarian LH/hCG receptors.