CHANGES IN FOREBRAIN AND PITUITARY DOPAMINE AND SEROTONIN CONTENTS OFFEMALE FUNDULUS DURING ITS BIWEEKLY REPRODUCTIVE-CYCLE

The biweekly spawning teleost, Fundulus heteroclitus, is an interestin g biological model that has its spawning cycle synchronized with the t ides coincident with the new and full moon. Changes in the dopamine (D A) and serotonin (5-HT) contents in the telencephalon, hypothalamus, a nd pituitary in female F, heteroclitus were monitored, as the fish pro gressed through the highly compressed course of events ranging from ov arian recrudescence, spawning and postspawning within a period of 14 d ays. Whereas DA levels in telencephalon and pituitary were high during ovarian recrudescence, a significant reduction was observed in the fi sh sampled during ovulation and spawning. 5-HT in the pituitary displa yed a similar pattern, however, that in the hypothalamus gradually inc reased during the cycle. 5-HT in the telencephalon did not change thro ugh the cycle. In view of the correlative changes between monoamine co ntent in the brain areas and the status of the ovary, occurring within a span of few days, the killifish emerges as a novel model to study t he neuroendocrine regulation of GtH in teleosts. (C) 1997 Elsevier Sci ence Inc.