Domperidone treatment advances onset of puberty in the viviparous mosquitofish Gambusia affinis

Abstract Background Although dopamine (DA) exerts modulatory effect on reproduction in the majority of fishes, its role is not clearly understood in viviparous species. The aim of this investigation was to determine the influence of DA antagonist domperidone (DOM) on puberty in the viviparous species Gambusia affinis. Results Treatment of 1.5 or 4 mg DOM to 25 days post-hatching (DPH) juveniles for a period of 35 days resulted in dense aggregations of gonadotropin-releasing hormone (GnRH)-immunoreactive fibres in the proximal pars distalis (PPD) region of the pituitary gland in contrast to faintly seen fibres in treatment controls. In the ovary, the follicles belonging to stages I–IV did not differ significantly among different experimental groups. However, stage V (vitellogenic) follicles were completely absent in treatment controls in contrast to their presence in 1.5 or 4 mg DOM-treated fish. Besides, the diameter of stage V follicles was significantly higher in 1.5 mg DOM-treated fish compared with 4 mg DOM-treated fish. Conclusions The results suggest that DOM treatment triggers the follicular development and promotes the early onset of puberty, possibly by attenuating the dopaminergic inhibition on GnRH fibres, for the first time in a viviparous species.

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Release of Luteinizing Hormone from the Anterior Pituitary Gland in vitro Can Be Concurrently Regulated by at Least Three Peptides: Gonadotropin-Releasing Hormone, Oxytocin and Neuropeptide Y

Neuroendocrinology ◽

10.1159/000054659 ◽

2001 ◽

Vol 73 (6) ◽

pp. 408-416 ◽

Cited By ~ 11

Author(s):

John J. Evans ◽

Fiona L. Pragg ◽

Drusilla R. Mason

Keyword(s):

Luteinizing Hormone ◽

Pituitary Gland ◽

Neuropeptide Y ◽

Anterior Pituitary ◽

Gonadotropin Releasing Hormone ◽

Anterior Pituitary Gland ◽

Releasing Hormone

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Distribution of lamprey gonadotropin-releasing hormone in the brain and pituitary gland of larval, metamorphic, and adult sea lampreys, Petromyzon marinus

Canadian Journal of Zoology ◽

10.1139/z94-008 ◽

1994 ◽

Vol 72 (1) ◽

pp. 48-53 ◽

Cited By ~ 26

Author(s):

Glenda M. Wright ◽

Kim M. McBurney ◽

John H. Youson ◽

Stacia A. Sower

Keyword(s):

Pituitary Gland ◽

Preoptic Area ◽

Petromyzon Marinus ◽

Gonadotropin Releasing Hormone ◽

Immunoperoxidase Technique ◽

Dorsal Region ◽

Releasing Hormone ◽

Sea Lampreys ◽

The Brain

Lamprey gonadotropin-releasing hormone was demonstrated in the brains of larval, metamorphic, and adult sea lampreys, Petromyzon marinus, using an immunoperoxidase technique. Gonadotropin-releasing hormone was observed in the neurohypophysis and preoptic area of the brain of larval, metamorphic, juvenile, and prespawning adults. The occurrence of immunoreactive cells and the intensity of the immunostaining was lowest in larvae, but by stage 5 of metamorphosis there was a marked increase in the prevalence and staining of these cells, which continued into adults. In larvae and lampreys in metamorphic stages 1–4, most immunoreactive fibres were confined to the dorsal region of the neurohypophysis. During stage 5 there was an expansion of immunopositive fibres into the ventral portion of the neurohypophysis. Prominent immunoreactivity was observed throughout the neurohypophysis from stage 5 onward through the adult stages. Changes in immunoreactivity of these cells and fibres in the brain and neurohypophysis correlate well with increased concentrations of hormone in the brain during development and with the timing of presumed changes in activity of cells in the adenohypophysis during metamorphosis.

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