The dopminergic inhibition of the gonadotropin-releasing hormone-induced gonadotropin release: An in vitro study with fragments and cell suspensions from pituitaries of the African catfish, Clarias gariepinus (Burchell)

Dynamic characteristics of serotonin and dopamine metabolism in the rainbow trout brain: a regional study using liquid chromatography with electrochemical detection

“…The literature concerning a dopamine-induced inhibitory effect of the gonadotropin (GtH) release is well documented, specially for the goldfish and to a lesser extent for the other species. A direct dopamine inhibition of both spontaneous and GtH-releasing hormone induced GtH release was demonstrated in vitro in goldfish (Chang et al 1984a) and in the catfish (De Leeuw et al 1986). A temporal increase in serum GtH levels in response to domperidone was correlated to the time course of pituitary accumulation of [ 3 H] domperidone (Omeljaniuk et al 1987).…”

“…Histochemical fluorescent, immunocytochemical or autoradiographic methods allow cells containing amines or amine receptors to be localised in brain tissue from several fishes: eel (Popek 1983), goldfish (Kah et al 1984a(Kah et al , 1986, salmon and rainbow trout (Terlou and Ekengren 1979). Pharmacological experiments in fish, focused on the relationships between brain metabolites and neurohormonal secretions of the pituitary, have delineated the important role of aminergic metabolism (Peter and Paulencu 1980;Billard et al 1984;Chang et al 1984a, b;De Leeuw et al 1986;Van Der Kraak et al 1986). However, HPLC-ECD methods have not been used extensively (Sebert et al 1985).…”

The effect of pimozide/LHRHa and 17α-hydroxyprogesterone on plasma steroid levels and ovulation in the African catfish, Clarias gariepinus

“…and pimozide (PIM) (De Leeuw et al, 1985a, b). The LHRH acts by stimulating the release of gonadotropin from the pituitary, and the pimozide by suppressing the action of a natural hypothalamic gonadotropin release-inhibiting factor ( GRIF) which has been identified as dopamine (DA) Peter and Paulencu, 1980;Chang and Peter, 1983;Chang et al, 1984;De Leeuw et al, 1986). The same combination of compounds had been shown to induce oocyte maturation and ovulation in the goldfish, Carussius aurutus (Chang and Peter, 1983;Sokolowska et al, 1984)) carp, Cyprinus carpio (Billard et al, 1983) and loach, Purumisgurnus dubryunus (Lin et al, 1985).…”

Dopaminergic influence on gonadotropin secretion in white sturgeon (Acipenser transmontanus)

“…Additional evidence from other teleost species has also supported the concept of a dopaminergic inhibition of GTH secretion. In African catfish, Clarias gariepinus (DeLeeuw et al 1986), Chinese loach, Paramisgurnus dabryanus (Lin et al 1989), common carp Cyprinus carpio (Lin et al 1993(Lin et al , 1994, and tilapia (Levavi-Sivan et al 1995) dopamine or its agonist, apomorphine, blocked GnRH-stimulated GTH release. The potentiation of GnRH-induced GTH secretion has been observed in several teleost species using the dopamine receptor antagonists pimozide or domperidone, including goldfish (Chang and Peter 1983b;Chang et al 1984c;Sokolowska et al 1985), African catfish (DeLeeuw et al 1985), Chinese loach (Lin et al 1986(Lin et al , 1991, common carp , coho salmon, Oncorhynchus kisutch ), rainbow trout, Salmo gairdneri (Billard et al 1984), European eel, Anguilla anguilla (Dufour et al 1988) and bream, Parabramis pekinensis .…”