Science & Technologies Volume IV, Number 1, 2014 Medicine 40 EFFECT OF TESTOSTERONE PROPIONATE ON LEUCOPOIESIS IN EXPERIMENTAL CONDITION Delian P. Delev, Ilia D. Kostadinov, Ivanka I. Kostadinova, Maria Georgieva-Kotetarova Medical University – Plovdiv, Medical Faculty, Department Pharmacology and Clinical Pharmacology; 15A Vassil Aprilov Ave. 4002, Plovdiv, BULGARIA, Mobile: + 359 88 8 713731 . Correspondence to: delevg@gmail.com ABSTRACT: Introduction: The aging of the stronger gender is related with progressive with progressive decrease of the levels of serum testosterone (T). The epidemiological studies show an increase of the morbidity and mortality, associated with low levels of T in men in the process of aging. The benefits of testosterone replacement therapy (TRT) are undisputable. The reduction of the normal levels of T is associated with deprivation of erythropoiesis. There is scarce data about the influence of testosterone propionate on leucopoiesis in acute and chronic treatment, as in humans, thus experimentally. Aim: To study the dynamics in the values of serum testosterone and the number of the leucocytes during replacement therapy with testosterone propionate in dose 4 and 8 mg/kg body weight. (b.w.) in rat model of androgen deficiency. Materials and methods: 140 male rats (70 for acute and 70 for chronic trial) were used, distributed in the following groups-control orchiectomized .simulative operated controls treated with 4 and 8 mg/kg b. w. testosterone propionate, orchiectomized animals, aged male controls and trial animals treated with 4 and 8 mg/kg b. w. testosterone propionate. Results and discussion: Orchiectomy lowered significantly the levels of serum T at the 15 days trial and insignificantly at chronic one. The supplementation with testosterone propionate raised its levels at the higher dose. In the aged rats an increase of the serum levels of T was observed, a result from the application of its propionate salt. Significance was received when the dose 8 mg/kg b. w. was used. Castration significantly increased the number of the leucocytes at the 15 days traced animals, compared with the sham operated (p = 0, 04). The application of testosterone does not change significantly this effect in both doses studied. Respectively the groups treated with 4 mg/kg b. w. and 8 mg/kg b. w. testosterone propionate significantly (р = 0,008; р = 0,033) differ from sham operated controls by the number of leucocytes. At the chronic trial testosterone propionate significantly raises the number of the leucocytes towards controls as in dose 4 mg/kg b. w. (р = 0,011; р = 0,007), thus in dose 8 mg/kg b. w. (р < 0,0001). There is no authoritative difference in the influence over the number of the leucocytes between the two doses. Conclusions: 1. 8 mg/kg b.w. of testosterone propionate, applied in rat model of androgen deficiency restores the physical T levels. 2. Leucocyte stimulation was observed in 15 days testosterone propionate treated rats with androgen deficiency. Key words: testosterone propionate, leucocytes, leucopoiesis androgen deficiency, rat model. Introduction: The process of aging of the stronger gender is related with progressive decrease of the level of the serum testosterone (T) 1 . Epidemiological researches show an increase in morbidity and mortality, associated with low level of T in men with the progress of age. The benefits of testosterone replacement therapy are indisputable. Libido and sexual function are improved, bone density, muscle strength 2 , mood and cognitive functions are increased, cardio- vascular risk and the manifestations of metabolic syndrome are diminished 3 . T has favorable effect on vascular reactivity, inflammation, production of cytokines, expression of adhesion molecules, insulin resistance, concentrations of serum lipids and factors of the hemostasis 4 etc. Androgens influence hemostasis. Before the introduction of the recombinant hemopoetic growth factors, they have been used as basic pharmacological instruments for stimulation of the production of erythrocytes. Indications for treatment have been aplastic anemia 5 and renal