Production of Recombinant Goldfish Prolactin and Its Applications in Radioreceptor Binding Assay and Radioimmunoassay

Wong, Anderson O. L.; Cheung, Hilda Yeuk-Siu; Lee, Eric K.Y.; Chan, King Ming; Chen, Cheng

doi:10.1006/gcen.2001.7771

Cited by 13 publications

(6 citation statements)

References 52 publications

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“…Conversely, GH and SL increased TRAP activities, indicating the specificity of the suppressive action of PRL in the osteoclasts. Furthermore, this in-vitro effect of PRL on goldfish scales occurred at a very low concentration (10 pg/ml), which was within the range of plasma PRL concentrations (~0.1-10 ng/ml) in teleosts, including the goldfish (Wong et al, 2002). Such a direct and specific effect of PRL has not been demonstrated before in teleosts, although PRL has been recognized to act on various tissues (see Sakamoto et al, 2003).…”

Section: Discussionmentioning

confidence: 53%

Prolactin Inhibits Osteoclastic Activity in the Goldfish Scale: A Novel Direct Action of Prolactin in Teleosts

et al. 2008

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In teleosts, prolactin is involved in calcium regulation, but its role in scale/bone metabolism is unclear. Using the in-vitro system with goldfish scales developed recently, we explored the effects of teleost prolactin, growth hormone, and somatolactin on osteoclasts and osteoblasts. Addition of prolactin at concentrations of 0.01-100 ng/ml reduced osteoclastic activity, partly via osteoclast apoptosis, after 6-18 h incubation. Conversely, growth hormone and somatolactin at a concentration of 100 ng/ml increased osteoclastic activity after 18 h incubation, indicating the specificity of the inhibitory effect of prolactin on osteoclastic activity. On the other hand, these three hormones promoted osteoblastic activity at concentrations of 10-100 ng/ml. The results from this study are the first demonstration of direct effects of prolactin on scale/bone metabolism and osteoclastic activity in a teleost.

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Section: Discussionmentioning

confidence: 53%

Prolactin Inhibits Osteoclastic Activity in the Goldfish Scale: A Novel Direct Action of Prolactin in Teleosts

et al. 2008

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“…The mature peptide coding regions were inserted into a prokaryotic SUMO vector (a gift from Dr. Shannon W. N. Au at The Chinese University of Hong Kong) by taking advantage of the Bam HI/ Eco RI sites of the SUMO vector. After protein induction and purification [39], the polypeptide was recovered through removing the SUMO tag on a nickel column by virtue of its hexa-His motif after a SUMO-specific protease SENP1 (sentrin-specific protease 1) digestion from the fusion protein. Polyclonal antibodies against the recombinant zfPRL2 were prepared in New Zealand White rabbits as previously described [40].…”

Section: Methodsmentioning

confidence: 99%

Discovery of a Novel Prolactin in Non-Mammalian Vertebrates: Evolutionary Perspectives and Its Involvement in Teleost Retina Development

et al. 2009

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BackgroundThe three pituitary hormones, viz. prolactin (PRL), growth hormone (GH) and somatolactin (SL), together with the mammalian placental lactogen (PL), constitute a gene family of hormones with similar gene structure and encoded protein sequences. These hormones are believed to have evolved from a common ancestral gene through several rounds of gene duplication and subsequent divergence.Principal FindingsIn this study, we have identified a new PRL-like gene in non-mammalian vertebrates through bioinformatics and molecular cloning means. Phylogenetic analyses showed that this novel protein is homologous to the previously identified PRL. A receptor transactivation assay further showed that this novel protein could bind to PRL receptor to trigger the downstream post-receptor event, indicating that it is biologically active. In view of its close phylogenetic relationship with PRL and also its ability to activate PRL receptor, we name it as PRL2 and the previously identified PRL as PRL1. All the newly discovered PRL2 sequences possess three conserved disulfide linkages with the exception of the shark PRL2 which has only two. In sharp contrast to the classical PRL1 which is predominantly expressed in the pituitary, PRL2 was found to be mainly expressed in the eye and brain of the zebrafish but not in the pituitary. A largely reduced inner nuclear layer of the retina was observed after morpholino knockdown of zebrafish PRL2, indicating its role on retina development in teleost.SignificanceThe discovery of this novel PRL has revitalized our understanding on the evolution of the GH/PRL/SL/PL gene family. Its unique expression and functions in the zebrafish eye also provide a new avenue of research on the neuroendocrine control of retina development in vertebrates.

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“…It might be that an inhibitory tonus maintained low cAMP levels in trout PRL cells in vivo. This can be achieved through dopamine, cortisol, and somatostatin (42,43). In vitro, the absence of such an inhibitory input would result in a maximal accumulation of cAMP, making any stimulation by forskolin ineffective.…”

Section: Melatonin Modulates Prl Release By Trout Lactotropesmentioning

confidence: 97%

Melatonin Modulates Secretion of Growth Hormone and Prolactin by Trout Pituitary Glands and Cells in Culture

et al. 2003

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In Teleost fish, development, growth, and reproduction are influenced by the daily and seasonal variations of photoperiod and temperature. Early in vivo studies indicated the pineal gland mediates the effects of these external factors, most probably through the rhythmic production of melatonin. The present investigation was aimed at determining whether melatonin acts directly on the pituitary to control GH and prolactin (PRL) secretion in rainbow trout. We show that 2-[125I]-iodomelatonin, a melatonin analog, binds selectively to membrane preparations and tissue sections from trout pituitaries. The affinity was within the range of that found for the binding to brain microsomal preparations, but the number of binding sites was 20-fold less than in the brain. In culture, melatonin inhibited pituitary cAMP accumulation induced by forskolin, the adenyl cyclase stimulator. Forskolin also induced an increase in GH release, which was reduced in the presence of picomolar concentrations of melatonin. At higher concentrations, the effects of melatonin became stimulatory. In the absence of forskolin, melatonin induced a dose-dependent increase in GH release, and a dose-dependent decrease in PRL release. Melatonin effects were abolished upon addition of luzindole, a melatonin antagonist. Our results provide the first evidence that melatonin modulates GH and PRL secretion in Teleost fish pituitary. Melatonin effects on GH have never been reported in any vertebrate before. The effects result from a direct action of melatonin on pituitary cells. The complexity of the observed responses suggests several types of melatonin receptors might be involved.

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Production of Recombinant Goldfish Prolactin and Its Applications in Radioreceptor Binding Assay and Radioimmunoassay

Cited by 13 publications

References 52 publications

Prolactin Inhibits Osteoclastic Activity in the Goldfish Scale: A Novel Direct Action of Prolactin in Teleosts

Prolactin Inhibits Osteoclastic Activity in the Goldfish Scale: A Novel Direct Action of Prolactin in Teleosts

Discovery of a Novel Prolactin in Non-Mammalian Vertebrates: Evolutionary Perspectives and Its Involvement in Teleost Retina Development

Melatonin Modulates Secretion of Growth Hormone and Prolactin by Trout Pituitary Glands and Cells in Culture

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