Effect of the lack of gonadal hormones on the calcium level of tibia bone in rats

Gonadal hormones have effect on the growth through increasing the osteoblastic activity of bone. They have influence on the calcium metabolism and therefore, are influential on the calcium level of serum and the strength of the bones. The purpose of this study is to examine the effects of gonadal hormones deficiency on the percentage of bone calcium of the tibia in rats.

In the present experimental study 50 thirty – day – old Wistar rats comprised the sample. 25 male rats were randomly divided into 2 groups: Experimental group, i.e. orchidectomy ORX, (n=15) and control group, sham- operation, (n=10) and also 25 female rats were divided in the same way into 2 groups: Experimental group, i.e. ovariectomy OVX, (n=15) and control group, sham- operation, (n=10). Samples were sacrificed 6 months after the surgery i.e. orchidectomies, ovariectomies, and sham operations. Percentage of bone calcium was determined by atomic absorption spectrophotometry. Serum testosterone, progesterone and estradiol levels were measured by ELISA.

Serum testosterone level significantly decreased in the ORX group as compared with the male sham- operated group. In this study estradiol level was not changed in OVX group, but despite the significant decrease in progesterone level (p<0.001), no significant differences in all variables were found between the OVX group and female sham- operated group. In the ORX group, body length and weight, were significantly smaller than in the male sham- operated group. No significant difference in bone calcium percentage was found (Student’s t-test) between control and experimental groups.

In conclusion, it seems that the suppression of gonadal hormones secretion in the growth phase cannot decrease calcium percentage of tibia bone in rats.