Rats have MUPs too - but different!

Gómez-Baena G, Armstrong SD, Phelan MM, Hurst JL, Beynon RJ. (2014). The major urinary protein system in the rat. Biochem Soc. Trans. 42: 886-892

The genomes of rats and mice both contain a cluster of multiple genes that encode
small (18-20 kDa) eight-stranded β-barrel lipocalins that are expressed in
multiple secretory tissues, some of which enter urine via hepatic biosynthesis.
These proteins have been given different names, but are mostly generically
referred to as MUPs (major urinary proteins). The mouse MUP cluster is
increasingly well understood, and, in particular, a number of roles for MUPs in
chemical communication between conspecifics have been established. By contrast,
the literature on the rat orthologues is much less well developed and is
fragmented. In the present review, we summarize current knowledge on the MUPs
from the Norway (or brown) rat, Rattus norvegicus.