Changes in Growth Hormone and Cortisol Profile Due to Lead Induced Toxicity in Labeo rohita

The present study was conducted to investigate the effect of lead (Pb) on the growth hormone (GH) and plasma cortisol level of common carp, Labeo rohita. One hundred Labeo rohita were divided in two equal groups; control and treated. Treated fishes were exposed to 1.4mg/l of lead acetate (1.9% lead concentration i,e., LC50) at the interval of 72 hours for a period of five weeks. Blood was collected from the caudal vein of fish from both treated and control groups, after week interval. Mean body weight of treated group decreased significantly as compared to the control group (P<0.001) on weekly basis. GH decreased significantly (P<0.001) in the treated group from first week to the last week of the treatment as compared to the control group. In treated groups, the plasma cortisol level increased gradually from week 1 to week 5. Significant negative correlation between GH concentration and cortisol level (Pearson r=-0.94) was observed. It is concluded that Pb acts as endocrine disrupter in fish bodies by altering the pattern of synthesis and metabolism of cortisol as well as GH. Elevation in basal cortisol level markedly influences the growth rate by decreasing the GH ultimately decreasing body weight of animal.