+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Innervation of the pars intermedia and control of alpha-melanotropin secretion in the newt



Innervation of the pars intermedia and control of alpha-melanotropin secretion in the newt



Neuroendocrinology 50(5): 543-549



In this study we have investigated the presence of nerve fibers containing dopamine, thyrotropin-releasing hormone (TRH) and neuropeptide Y (NPY) in the pars intermedia of the crested newt and we have examined the possible effect of these neurohormones on the release of alpha-melanotropin (alpha-MSH) by neurointermediate lobes in vitro. By means of immunohistochemistry, we observed the presence of tyrosine hydroxylase (TH)-immunoreactive fibers in the pars intermedia of the crested newt. Using a specific antiserum to dopamine, these fibers appeared to be mainly dopaminergic in nature. Unlike anurans, urodele amphibians do not exhibit TRH or NPY-like immunoreactivity in the pars intermedia. A perifusion system technique for newt pituitaries was developed to investigate the effect of dopamine, TRH and NPY on alpha-MSH secretion. Administration of increasing concentrations of dopamine (from 10(-9) to 10(-5)M) induced a dose-related inhibition of alpha-MSH release. This inhibitory effect was mimicked by the dopamine agonist apomorphine (10(-6)M). In contrast, the secretory activity of the newt pars intermedia was not affected by administration of synthetic TRH or NPY (up to 10(-7) and 10(-6)M, respectively). These results indicate that the neurotransmitter dopamine likely plays a pivotal role in the regulation of melanotropin secretion in urodele amphibians.

Please choose payment method:






(PDF emailed within 1 workday: $29.90)

Accession: 040455372

Download citation: RISBibTeXText

PMID: 2514395


Related references

Innervation of the Pars intermedia and Control of Alpha-Melanotropin Secretion in the Newt. Neuroendocrinology 50(5): 543-549, 1989

Immuno reaction alpha melanotropin and beta endorphin in the toad xenopus laevis pars intermedia dissociation in storage secretion and sub cellular localization. Life Sciences 29(15): 1599-1605, 1981

Effects of 6 hydroxy dopamine on the innervation of the pituitary pars intermedia in the crested newt. Journal of Submicroscopic Cytology 6(1): 117-118, 1974

Immunological evidence for multiple forms of alpha-melanotropin (alpha-MSH) in the pars intermedia of the Australian lungfish, Neoceratodus forsteri. General and Comparative Endocrinology 71(3): 468-474, 1988

Isolation of alpha-melanotropin from the pars intermedia of the larval amphibian, Ambystoma tigrinum. General and Comparative Endocrinology 68(2): 322-330, 1987

Processing of 2 forms of the common precursor for alpha melanotropin and beta endorphin in the rat pars intermedia. Biologie Cellulaire (Ivry Sur Seine) 36(2): 119-126, 1979

Concomitant synthesis of beta-endorphin and alpha-melanotropin from two forms of pro-opiomelanocortin in the rat pars intermedia. Proceedings of the National Academy of Sciences of the United States of America 76(10): 5085-5089, 1979

Steady state analysis of alpha melanotropin in the pars intermedia of anolis carolinensis effects of background adaptation. General & Comparative Endocrinology 68(1): 152-160, 1987

Processing of 2 forms of the common precursor to alpha melanotropin and beta endorphin in the rat pars intermedia evidence for and partial characterization of new pituitary peptides. European Journal of Biochemistry 110(2): 387-396, 1980

Pars intermedia control with and without innervation studies in elasmobranchs and a lizard. Knowles, Francis And Lutz Vollrath (Ed ) Neurosecretion The Final Neuroendocrine Pathway Vi International Symposium London, England 1973 Ix+345p Illus Springer-Verlag: New York, N Y , U S A ; Berlin, West Germany ISBN 0-387-06821-X; ISBN 3-540-06821-X: 198-206, 1974

Biosynthesis of a 3-Melanotropin-like Peptide in the Pars Intermedia of the Amphibian Pituitary Gland. Febs Journal 126(1): 23-28, 1982

Noradrenaline inhibition of melanotropin release in incubates of toad pars intermedia. General & Comparative Endocrinologyppl 3: 108-113, 1972

CRF stimulates alpha-MSH secretion and cyclic AMP accumulation in rat pars intermedia cells. Life Sciences 31(19): 2129-2135, 1982

Biosynthesis of a gamma 3-melanotropin-like peptide in the pars intermedia of the amphibian pituitary gland. European Journal of Biochemistry 126(1): 23-28, 1982

Biosynthesis of melanotropin and related peptides in the pars intermedia of the mouse a pulse chase analysis. Molecular & Cellular Endocrinology 13(2): 149-158, 1979