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1.
Endocrine ; 22(3): 225-37, 2003 Dec.
Article in English | MEDLINE | ID: mdl-14709795

ABSTRACT

Pituitary adenylate cyclase-activating polypeptide (PACAP) and vasoactive intestinal polypeptide (VIP) immunoreactive cells were demonstrated in the hypothalamic magnocellular nuclei in cats and rats. In cats these immunoreactive cells were stained without any treatment or intervention; however, in rats we had to use the pituitary stalk section to enhance the amount of PACAP and VIP for successful immunostaining. In both species the regions occupied by PACAP and VIP immunoreactive cells partially overlap each other in the paraventricular and supraoptic nuclei. Nevertheless, in either cats or rats PACAP and VIP immunoreactivities do not colocalize in the same cells studied by double labeling immunohistochemistry (IHC) or by the combination of immunohistochemistry and in situ hybridization. As was expected, PACAP and VIP immunoreactive materials were stored in different fibers of the posterior pituitary where the distribution of PACAP and VIP fibers also showed different patterns: PACAP fibers form a dense plexus at the periphery of the posterior lobe, in the vicinity of the intermediate lobe; however, the VIP fibers were evenly distributed mainly in the center of the posterior lobe. In spite of the high sequence homology of PACAP and VIP, the two peptides are synthesized in different subpopulations of hypothalamic neurons. This different distribution correlates well with the different role of the hypothalamic PACAP and VIP in the biologic clock and in the functions of the anterior and posterior pituitary.


Subject(s)
Hypothalamus/metabolism , Neuropeptides/metabolism , Pituitary Gland, Posterior/metabolism , Vasoactive Intestinal Peptide/metabolism , Animals , Cats , Cell Nucleus/metabolism , Immunohistochemistry , In Situ Hybridization , Male , Neuropeptides/genetics , Pituitary Adenylate Cyclase-Activating Polypeptide , Rats , Rats, Sprague-Dawley
2.
Med Sci Monit ; 8(2): SR5-20, 2002 Feb.
Article in English | MEDLINE | ID: mdl-11862161

ABSTRACT

The presence of PACAP and VIP was demonstrated in all the four levels of the photoneuroendocrine system (PNES) with the use of immunohistochemistry (IHC), radioimmunoassay (RIA), anterograde and retrograde tracing techniques, and cell immunoblot assay (CIBA). Both peptides play a physiological role in the PNES. According to our results both PACAP and VIP are involved in the regulation of the gonadotrop hormone secretion and their inhibitory role may be mediated through the neuronal chain of the PNES.


Subject(s)
Neuropeptides/metabolism , Neurosecretory Systems/metabolism , Vasoactive Intestinal Peptide/metabolism , Animals , Immunohistochemistry , Pituitary Adenylate Cyclase-Activating Polypeptide , Rats
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