In mammals, the primary transcript that generates flGHR mRNA may undergo processing that includes post-transcriptional modifications, which generate mRNAs of various lengths. These can encode for short forms of the GHR, such as truncated GHRs (tGHRs) and GH binding proteins (GHBPs) (Edens and Talamantes, 1998). tGHRs are membrane-anchored proteins with an extracellular GH binding site, but they lack the majority of intracellular domain necessary for signal transduction. Therefore, they may abolish the GH signal and act as dominant negatives of GH function.