TM rats: a model for platelet storage pool deficiency.

TM rats have a light brown hooded coat pattern resembling that of Fawn hooded (FH) rats which are a model of platelet storage pool deficiency (SPD). We examined whether the TM strain has the same platelet SPD as the FH strain. TM rats had a prolonged bleeding time and a low blood serotonin level, although their blood coagulation time and platelet counts were normal. The light coat color of the TM strain was judged to be associated with the red-eyed dilution gene as in the FH strain, but not pink eye dilution as in the RCS rat strain. Platelet SPD seen in TM rats may be a pleiotropic effect of the red-eyed dilution gene proposed in FH rats, Despite these similarities, the genetic background of the TM strain was obviously different from that of the FH strain. The TM strain, developed independently of the FH strain, will therefore be used as a model of platelet SPD.