Abstract: The invention relates to the field of regulating metabolic processes, for example, to regulate the presence and/or activity of a receptor at the surface of a cell. The invention provides a method for controlling the presence of a receptor at the surface of a cell comprising interfering with the interaction of an F-box protein with a ubiquitin/proteasome binding site of the receptor, wherein the ubiquitin/proteasome binding site comprises particular amino acid sequences. The invention further provides a method for controlling the presence of a growth hormone receptor (GHR) at the surface of a cell comprising interfering with the interaction of an F-box protein with a ubiquitin/proteasome binding site of the GHR.