Effect of 5-hydroxyindoles (5-HT and 5-HTP) on pineal biochemical constituents of F. Pennanti

Abstract

In the pineal gland (PG) 5-hydroxytryptamine (5-HT) or serotonin is highly concentrated in comparison to other parts of the brain. It is the precursor of the formation of various hydroxy- and methoxyindoles whose reproductive effects are well known. However, the effect of serotonin on the PG itself is less extensively known. In the present experiment an attempt was made to study the effect of morning (0830-0930) injection of 5-HT (20 μg/day) and its intermediate product 5-hydroxytryptophan (5-HTP; 5 μg/day) on the biochemical constituents (protein, cholesterol and serotonin) of PG during the two phases of reproductive cycle (active/inactive) of Indian Palm Squirrel, Funambulus pennanti. The 5-hydroxyindoles suppressed the PG weight and its biochemical activities which initiated the unseasonal testicular recrudescence during reproductive inactive phase, whereas, no significant effect was noted on the pineal and testicular weight except the decrease in the serotonin content of PG during the reproductive active phase.