Measurement of prolactin (PRL), growth hormone (GH), insulin-like growth factor-I (IGF-I), cortisol and insulin in gilthead seabream Sparus auratus

The role of GH, IGF-I, PRL, insulin and cortisol is very important in fish growth and metabolism. The aim of this pilot study was to use of human diagnostic kits, based on the method of chemiluminescence, to determine the highly conserved hormones in teleost fish seabream (Sparus auratus) farmed in floating marine cages. Blood was sampled from six adult male individuals. Total protein levels exhibited values from 2.9 to 4.2 g/dl. Cholesterol mean value (mv) in plasma was 292 mg/dl vs 267 mg/dl in serum. Glucose mv was higher in plasma (97 mg/dl) than in serum (76 mg/dl). Insulin levels ranged from 1.24 to 1.40 μIU/ml, PRL was undetectable. GH levels range 0.033-0.046 ng/ml. IGF-I mv was measured 29.16 ng/ml in plasma and 12.83 ng/ml in serum, Cortisol mv was 9.8 and 7.2 μg/dl in plasma and serum respectively. No significant differences were observed between fed and fasting condition, similarly with anesthetized and non anesthetized individuals. These preliminary data are so far to be thought conclusive. However, the results are indicative of the fact that human kits, based on the method of chemiluminescence, properly modified, could be used for hormonal evaluation in fishes.