The overall objective of this project is to understand the biology of the glycoprotein hormones (thyrotropin, chorionic gonadotropin, luteinizing hormone, and follicle-stimulating hormone). Methods for more sensitive and accurate measurement of thyrotropin and chorionic gonadotropin in biologic fluids have been developed. Studies of structure-function relationships indicate that biochorionic gonadotropin and luteinizing hormone have intrinsic follicle-stimulating and thyroid-stimulating activities. The emphasis of the project in the coming year will be on the distribution, renal excretion, metabolism, and degradation of glycoprotein hormones and on the mechanisms of structural, immunological, and biological heterogeneity of glycoprotein hormones.