Chronic administration of ND at high dose decreased plasma FSH, LH, testosterone, weight gain and food and water intake in male rats. In addition, erythrocytes; hemoglobin, hematocrit, Leukocyte and platelets values were increased in group T. High doses of AAS used for athletic enhancement can lead to irreversible organ damage such as reduced fertility and gynecomastia in males (
9). Moreover, AAS has a high affinity for the androgen receptor in central and peripheral tissues and causes impairments in hypothalamicpituitary-gonadal axis (
9). In addition, Kuhn CM reported that AAS affects androgen receptors and alters enzymatic aromatization of testosterone derivatives to increase its affinity to estrogen receptors (
10). Our finding exposed that ND decreased serum LH and testosterone secretion in the group T. These results are the same as Alsio (
11), which reported that AAS administration was probable to reduce hypothalamic-pituitary-gonadal axis activity by affecting physiological feedback mechanisms. Bijlsma et al. (
7) in a pilot study found that ND administration in male patients with rheumatoid arthritis caused significant decreases in serum Testosterone and FSH levels. Our findings showed that FSH value in group T was significantly deceased compared to that of other groups and it was the same as literature study (
10). Oda and El-Ashmawy (
12) reported that chronic administration of ND caused decrease in testes and epididymis weights, but did not show any significant changes in weight gain in normal rabbits. Our results are different with that of Oda and El-Ashmawy (
12). This difference is probably due to different used animals. Our findings were in accordance with the theory that sex steroids hormones can act directly on the hypothalamus- pituitary-testis axis and resulting in selective FSH and LH secretion (
8). In addition, our outcome was in agreement with that of Shokri et al. (
13), which revealed that exercise training increases the amount of apoptosis in the spermatogenic cell lineage by supraphysiological dose of ND in rats. Our study revealed that weight gain, food and water intake in group T were significantly decreased compared to those of other groups, which is in accordance with the literature (
14). Bhasin et al. (
14) found that erythrocytes, hemoglobin and hematocrit were improved dose dependently in healthy men aged 18 to 50 years who received AAS and changes in levels of hemoglobin and hematocrit were related to changes in testosterone concentrations compared to those of placebo group. In the present study, erythrocyte, hemoglobin, hematocrit, leukocyte and platelets values in group T were significantly increased compared to those of other groups and confirmed by another investigation (
14). This is presumably because chronic ND administration in the present study increased metabolism, serum erythropoietin concentration and stimulated hematopoiesis in bone marrow.
In conclusion, chronic administration of high doses of ND administration could alter serum FSH, LH, testosterone, weight gain, food and water intake and hematological parameters in male rats.