Tissue polyamine concentrations in the European sea bass (Dicentrarchus labrax L.): change with age and season of the year.

Independently of the age of the European sea bass, putrescine and spermidine are much higher in liver and brain than in muscles, while spermine concentrations are more similar to one another. The polyamine concentrations are higher in 2 years old sea bass than in 1 year old fish except for heart spermidine and liver spermine. Lowering in water temperature causes a decrease in the concentration of spermidine and spermine in all tissues examined. Putrescine, however, increases in heart, caudal muscle, liver and brain and it is unchanged in red and dorsal muscles.

Effect of GnRH administration on blood polyamines and LH levels in normal and obese children.

Blood polyamines (spermidine and spermine) and LH levels have been studied after acute GnRH injection both in obese and normal weight children. In both groups LH values significantly increased after stimulation but reached higher peaks in normal children than in obese ones (P less than 0.05). On the contrary, polyamine levels increased significantly only in the normal weight children. LH peaked at 30 min and polyamines at 60 min after GnRH injection. On the basis of the proposed role of polyamines in hormone action and of our results, we suggest that polyamines may play a pivotal role in hormone responsiveness of hypothalamic-hypophyseal axis.