Testosterone Propionate Increased The Levels Of Dopamine And Its Metabolites As Well As Its Catabolic Enzymes In The Brain Of Rats During The Early Development

Androgen plays an important role in the development of central nervous system.Based on the boy predominance of Tourette`s syndrome(TS),the alleviation of tics after antiandrogen treatment,the exacerbation of tics following exogenous androgen supply and the enhanced dopaminergic systems in TS,it was presumed that the androgen brain signaling disturbance intervened developmental dopaminergic system.Therefore,in the present studies,testosterone propionate(TP)was injected subcutaneously into rats at postnatal day 7.LC-MS/MS,real time PCR and western blot were used to detecte the altered expression of dopamine(DA)and its metabolites(DOPAC,HVA)as well as its catabolic enzymes in the TP-treated rats to investigate the influence of early androgen treatment upon the mesencephalic dopaminergic neurons during the development.Objective: To investigate the influence of early androgen treatment upon the mesencephalic dopaminergic neurons during the development.Methods: Sixty 5-day old male Wistar rats were randomly divided into 3 groups,namely 3-week group,7-week group and 6-month group,20 rats in each group.The rats in each group were subdivided into normal control group(Con),testosterone propionate group(testosterone propionate,TP),flutamide group(Flutamide,Flu),flutamide pretreatment testosterone propionate group(Flu+TP).The rats in TP group were treated by subcutaneous injection of TP(0.5mg/),once a day for 14 days from seventh days after birth.The rats in Flu group were injected subcutaneously by flutamide(50mg/kg)from seventh days after birth.The rats in Flu+TP group were pretreated by flutamide as did in Flu group and testosterone propionate was given as did in TP group 1 hr following flutamide pretreatment.The rats in control group were given equal volume of sesame oil.The samples were collected from rats in corresponding group respectively at 3 weeks,7 weeks and 6 months after birth.LC-MS/MS,real-time quantitative PCR and Western blotting were used to detect the altered expression of DA and its metabolites(DOPAC,HVA)and catabolic enzymes(MAOA,MAOB,COMT)in the rats.Results:1 LC-MS/MS1.1 DA and its metabolites in the caudate putamenCompared with the rats in Con group,the content DA,DOPAC and HVA in the caudate putamen of 3-week and 7-week old rats in TP group increased significantly(P<0.01).There was no significant difference in the content DA,DOPAC and HVA between Con group and Flu+TP group(P>0.05).Compared with rats in TP group,the content DA,DOPAC and HVA in the caudate putamen of 3-week old rats in Flu+TP group significantly decreased(P<0.01).There was no significant difference in the content DA,DOPAC and HVA between Flu group and Flu+TP group(P>0.05).There was no significant difference in the content DA,DOPAC and HVA between 6-month each group(P>0.05).1.2 DA and its metabolites in the nucleus accumbensCompared with the rats in Con group,the content DA,DOPAC and HVA in the nucleus accumbens of 3-week and 7-week old rats in TP group increased significantly(P<0.01).There was no significant difference in the content DA,DOPAC and HVA between Con group and Flu+TP group(P>0.05).Compared with rats in TP group,the content DA,DOPAC and HVA in the nucleus accumbens of 3-week old rats in Flu+TP group significantly decreased(P<0.01).There was no significant difference in the content DA,DOPAC and HVA between Flu group and Flu+TP group(P>0.05).There was no significant difference in the content DA,DOPAC and HVA between 6-month each group(P>0.05).2 real time quantitative PCR2.1 The expression of MAOA,MAOB and COMT m RNA in the substantia nigraCompared with the rats in Con group,the expression of MAOA,MAOB and COMT in the substantia nigra of 3-week and 7-week old rats in TP group increased significantly(P<0.01).There was no significant difference in the expression of MAOA,MAOB and COMT between Con group and Flu+TP group(P>0.05).Compared with rats in TP group,the expression of MAOA,MAOB and COMT in the substantia nigra of 3-week old rats in Flu+TP group significantly decreased(P<0.01).There was no significant difference in the expression of MAOA,MAOB and COMT between Flu group and Flu+TP group(P>0.05).There was no significant difference in the expression of MAOA,MAOB and COMT between 6-month each group(P>0.05).2.2 The expression of MAOA,MAOB and COMT mRNA in ventral tegmental areaCompared with the rats in Con group,the expression of MAOA,MAOB and COMT in the ventral tegmental area of 3-week and 7-week old rats in TP group increased significantly(P<0.01).There was no significant difference in the expression of MAOA,MAOB and COMT between Con group and Flu+TP group(P>0.05).Compared with rats in TP group,the expression of MAOA,MAOB and COMT in the ventral tegmental area of 3-week old rats in Flu+TP group significantly decreased(P<0.05).There was no significant difference in the expression of MAOA,MAOB and COMT between Flu group and Flu+TP group(P>0.05).There was no significant difference in the expression of MAOA,MAOB and COMT between 6-month each group(P>0.05).3 Western blot3.1 The expression of MAOA,MAOB and COMT in Caudatoputamen.Compared with the rats in Con group,the expression of MAOA,MAOB,MB-COMT and S-COMT in the caudate putamen of 3-week and 7-week old rats in TP group increased significantly(P<0.01).There was no significant difference in the expression of MAOA,MAOB,MB-COMT and S-COMT between Con group and Flu+TP group(P>0.05).Compared with rats in TP group,the expression of MAOA,MAOB,MB-COMT and S-COMT in the caudate putamen of 3-week old rats in Flu+TP group significantly decreased(P<0.01).There was no significant difference in the expression of MAOA,MAOB,MB-COMT and S-COMT between Flu group and Flu+TP group(P>0.05).There was no significant difference in the expression of MAOA,MAOB,MB-COMT and S-COMT between 6-month each group(P>0.05).3.2 The expression of MAOA、MAOB and COMT in nucleus accumbensCompared with the rats in Con group,the expression of MAOA,MAOB,MB-COMT and S-COMT in the nucleus accumbens of 3-week and 7-week old rats in TP group increased significantly(P<0.01).There was no significant difference in the expression of MAOA,MAOB,MB-COMT and S-COMT between Con group and Flu+TP group(P>0.05).Compared with rats in TP group,the expression of MAOA,MAOB,MB-COMT and S-COMT in the nucleus accumbens of 3-week old rats in Flu+TP group significantly decreased(P<0.01).There was no significant difference in the expression of MAOA,MAOB,MB-COMT and S-COMT between Flu group and Flu+TP group(P>0.05).There was no significant difference in the expression of MAOA,MAOB,MB-COMT and S-COMT between 6-month each group(P>0.05).Conclusion:1 Early treatment of testosterone propionate enhanced the expression of DA,DOPAC and HVA in the brain of juvenile and adolescent rats and flutamide inhibited the effect of early treatment of testosterone propionate.2 Early treatment of testosterone propionate upregulated the expression of MAO and COMT in the brain of juvenile and adolescent rats and flutamide inhibited the effect of early treatment of testosterone propionate.