Abstract: Materials and methods for regulating lipid abundance by modulating Protease Activated Receptor 1 (PAR1) and Protease Activated Receptor 2 (PAR2) levels arc provided herein. In a first aspect, this document features a method that includes (a) identifying a mammal as having a condition characterized at least by impaired lipid production, impaired cholesterol production, or both impaired lipid production and impaired cholesterol production; and (b) administering to the mammal an inhibitor of PAR1 and/or PAR2 in an amount effective to increase lipid production and/or cholesterol production in the mammal.