Pineal gonad relationship with special reference to temporal synergism of neurotransmitter precursor drugs in domestic pigeon Columba livia domestica

Pineal gonadal hypothalamo hypophyseal axis was tested using two neurotransmitter precursor drugs (5-HTP and L-DOPA) at different time intervals in monogamous bird domestic pigeon Columba livia domestica. Male birds were divided in to three groups, each with eight individuals. Group 1 was vehicle treated (control) group. Group II (8 hr) group received 5-HTP and L-DOPA at 8 hr interval. Group III, (8 hr+mlt) group which received single dose of melatonin along with two daily injection of 5-HTP and L-DOPA per day at 8 hr interval. Administration of 5-HTP, L-DOPA and melatonin conducted for 13 days and results were obtained at 46^th day. 8 hr group showed significantly stimulatory (P<0.05) responses in body weight, plasma testosterone and plasma prolactin levels, while 8 hr+mlt group showed significantly inhibitory (P<0.05) effect in comparison to control. Similar results were obtained in the testicular size in both groups (II and III). Regressive stages of reproductive state by administration of neurotransmitter precursor drugs along with melatonin suggest possibility of changes in temporal synergism between pinealgonadal axis of hypothalamus under laboratory conditions.