Abstract: Methods and compositions are provided for modulating fat storage of animals by targeting the gene and gene products of cathepsins, particularly cathepsins L, K, and S, and especially cathepsin L. The method comprises: administering to the animal an agent that reduces an in vivo level of cathepsin L activity such that fat storage by the animal is reduced. The methods of the present invention can be used to diagnose obesity, diabetes and related diseases such as hyperinsulinmia, hyperglycermia, hypertension, cardiovascular diseases, muscular dystrophy and infertility, as well as to screen for agents that can be used therapeutics for these diseases.

Abstract: Methods and compositions are provided for modulating blood insulin levels of animals by targeting the gene and gene products of cathepsins, particularly cathepsins L, K, and S, and especially cathepsin L. The method comprises: administering to the animal an agent that reduces an in vivo level of cathepsin L activity such that the blood insulin level of the animal is reduced. The method can be used to treat hyperinsulinmia and related diseases such as insulin resistance, type II diabetes, and hyperglycermia.