Testosterone is responsible for gender distinction in all of male mammals. Primary and secondary attributes, the effect on skin, muscular growth increase and positive nitrogen balance, the effect on bone growth and calcium suppression, pelvic transformation, increasing base metabolism, influence on red blood cells and influence on electrolytes balance are some of systemic influences of this hormone. The hormone is a natural ester of testosterone as well as has a long term effect. It is certain that testosterone leads to some changes in blood factors because of its influence on bone marrow. Drug injection started five days following gonadectomy and was continued intra-peritoneal weekly. After sixty days blood sampling was done of the animals' tail; then hematologic parameters such as MCV, MCH, MCHC, red blood cell count, hemoglobin, and hematocrit were calculated. The results demonstrated that the rate of hemoglobin, platelet and RBC count in gonadectomy group received testosterone have a meaningful difference compared with other groups (P<0.05). There was no meaningful difference about the rate of fibrinogen, MCV, MCHC, among groups (P>0.05). Finally it can be said that the hematologic effects must be considered to prevent saver problems for patient.
