Effect  of  4 - nonylphenol on hepatosomatic,gonadosomatic indicators plasma  IgM immunogl-

obulin and  Lysozyme  activity were  studied in  immature  Koi  carp .  In  order to ,  fish  for  over  

three  weeks  received   intraperitoneal  injection  of  10  ,  50  and  100  microgram  per  gram   of   4 –

 nonylphenol  and  2   microgram  per  gram  of  17-β- estradiol per body  weight . Fish   samples were

 taken  on  days  0  and  22 . The concentration of  IgM  immunoglobulin  was  measured  by  proposed  

 method  of   Siwicki  and  Anderson  and  lysozyme  activity  was measured  by ELISA .liver Index (HSI)

and  ovarian  Index  (GSI ) in  females  and liver Index (HSI )in males was determined by Htun-Han.The  

results  showed  that  amount  of  IgM  immunoglobulin  at  concentration  50 micrograms of  4- nonyl-

phenol  (55/66± 2/51)  in  female  and  (59± 2/01)  in  male , and  also  at  treatment of  10 micrograms

of 4-nonylphenol(53± 1/01)was significantly increased compared with control group(P <0.05). But the

level  of  IgM mmunoglobulin  at  concentration 100 micrograms of  4-nonylphenol and 2  micrograms

of 17- β-estradiol were significantly decreased compared with concentrations of 10 and 50 micrograms

 of 4- nonylphenol (P<0.05). Also  the  amount of  Lysozyme activity at concentration  50  micrograms

 of  4 - nonylphenol (64/33± 2/08)  in female and  (62/66 ±  2/51) in male ,were significantly increased

compared with control group(P<0.05).But Lysozyme activity at high concentration of  4 - nonylphenol

(100  micrograms  per  gram) and 17-β-estradiol showed significantly  reduced compared with control

group (P<0.05). The  index  changes  of  the  liver and  ovaries in females and males, respectively.The

results of  this study indicated  that estrogens like 4-nonylphenol  doubt  could  immunological  disrupt

in  fish ,suppress the immune system and  by sex steroid activity  and  safety  balance ,the  fish  will  be  

susceptible  to various diseases and increase the risk of disease.