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We have previously reported that neuropeptide-Y (NPY) stimulates GH and gonadotropin-II (GtH-II) release from perifused pituitary fragments in the goldfish. Since the teleost pituitary is directly innervated by neurosecretory terminals from the brain, we further investigated the possible sites of action of NPY. Both synthetic human NPY and NPY-(18-36), an(More)
In goldfish (Carassius auratus), two distinct forms of gonadotropin-releasing hormone (GnRH), namely, salmon GnRH (sGnRH) and chicken GnRH-II (cGnRH-II), have been identified in the brain using chromatographic, immunological, and molecular cloning approaches. These two native GnRHs act on specific receptors in the anterior pituitary to stimulate the(More)
In vitro release of gonadotropin releasing hormone (GnRH) from slices of the preoptic-anterior hypothalamic (P-AH) region and fragments of the pituitary of goldfish was studied using a static incubation system. Release of GnRH from both tissue preparations was stimulated by depolarizing concentrations of extracellular potassium ions (K+). Other putative(More)
Incubation of cultured goldfish pituitary cells with 10 nM to 1 microM apomorphine (APO), a non-selective dopamine agonist, increased growth hormone (GH) release in a dose-dependent manner. GH release was also stimulated in a dose-dependent manner by 0.1 nM to 1 microM salmon gonadotropin (GTH)-releasing hormone (sGnRH), sGnRH analog, and chicken GnRH-II(More)
Dopaminergic regulation of gonadotropin-releasing hormone (GnRH) concentrations in discrete brain areas of male goldfish was studied using the centrally active dopaminergic agonist apomorphine and antagonist pimozide. Pimozide caused time- and dose-dependent increases in serum gonadotropin levels and accumulation of GnRH in the olfactory bulbs,(More)
A radioimmunoassay (RIA) for [Trp7, Leu8]gonadotropin-releasing hormone (sGnRH) was developed to determine the gonadotropin-releasing hormone (GnRH) content in discrete brain areas of female goldfish at different stages of ovarian development. Temporal changes in serum gonadotropin (GtH) and GnRH concentrations in discrete brain areas were measured during(More)
The influence of GABA on pituitary gonadotrophin (GTH) release in the goldfish was studied by means of in vivo and in vitro techniques. It was found that GABA injected intraperitoneally caused an increase of serum GTH levels in regressed or early maturing fish, but not in late maturing animals. Moreover, injection of a GABA transaminase inhibitor caused a(More)
Locomotion is a complex behavior affected by many different brain- and spinal cord systems, as well as by variations in the peripheral nervous system. Recently, we found increased gene expression for EphA4, a gene intricately involved in motor neuron development, between high-active parental strain C57BL/6J and the low-active chromosome substitution strain(More)
Two molecular forms of gonadotropin-releasing hormone (GnRH) were identified in the extracts of various brain areas, spinal cord and pituitary in female and male goldfish and had chromatographic and immunological properties similar to [His5, Trp7, Tyr8]-GnRH (cGnRH-II) and [Trp7,Leu8]-GnRH (sGnRH). Radioimmunoassay using different GnRH antisera after high(More)