[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

[Effect of sexual hormone elimination on the changes of craniofacial dimensions in rats]

It is well - known that sex hormones regulate bone metabolism. Sex steroids increase osteoblasts activities and affect growth, remodeling and bone homeostasis. The aim of this study was to examine the effects of sex hormones deficiency on craniofacial growth in rats. Fifty, thirty-day-old Wistar rats comprised the sample in this experimental study. 25 male rats were divided into 2 groups: Experimental group, ORX, [n=15] and control group, sham-operation, [n=10] and 25 female rats were divided in the same way: Experimental group, OVX, [n=15] and control group, sham-operation, [n=10]. Body length and weight were registered monthly. The rats were sacrificed 6 months after the surgery. Direct millimetric measurements of the skeletodental variables and the tibial length were obtained by using electronic caliper. Serum testosterone, progesterone and estradiol levels were measured by ELISA. One Way ANOVA, Tukey and Student t tests were used to analyze the data. Serum testosterone level significantly decreased in the ORX group as compared with the male sham-operated group. In the ORX group, body length and weight, coronoid height, mandibular length, mandibular arch length, midfacial width, midfacial length, midfacial height, calvarial width, maxillary arch width, premaxillary length, nasal bone height, facial width, basisphenoid bone length and tibia bone length were significantly smaller than in the male control group. Structures showing cartilaginous growth were influenced more than structures showing sutural growth. Estradiol level did not change in OVX group, but despite the significant decrease in progesterone level, no significant differences except weight were found between the OVX group and female control group. In conclusion, it is strongly suggested that the suppression of sex hormones secretion in the growth phase might inhibit craniofacial growth and results in poor craniofaeial development and developing malocclusion