Elsevier

Peptides

Volume 19, Issue 4, April 1998, Pages 643-647
Peptides

Original Articles
Regional Distribution of Urocortin-like Immunoreactivity and Expression of Urocortin mRNA in the Human Brain

https://doi.org/10.1016/S0196-9781(98)00012-6Get rights and content

Abstract

Regional distribution of urocortin-like immunoreactivity (UCN-LI) in the human brain was studied by radioimmunoassay and was compared with that of corticotropin-releasing hormone (CRH). In addition, the expression of UCN mRNA was examined by reverse transcriptase-polymerase chain reaction (RT-PCR) method. UCN-LI was detected in every region of brain examined, including hypothalamus, pons, cerebral cortex, and cerebellum. The concentrations of UCN-LI in the human brain were approximately 3 pmol/g wet weight in any brain region, and no marked regional difference was noted. On the other hand, the highest concentrations of CRH-LI were found in the frontal cortex, temporal cortex, and hypothalamus and the lowest in the pons. Reverse phase high-performance liquid chromatography of the UCN-LI in the human brain extract showed two immunoreactive peaks; one peak eluting earlier and one in the position of synthetic human UCN. RT-PCR showed that UCN mRNA was expressed in every region of brain examined. These findings indicated that UCN and UCN mRNA were widely expressed in the human brain.

Section snippets

Tissues

This study has been approved by the Ethics Committee of Tohoku University School of Medicine. Human brain tissues were obtained at autopsy performed at the Department of Pathology, Tohoku University Hospital within 4 h postmortem from six patients (four male and two female, 31–74 years old). These patients had no neurological or endocrinological diseases. The tissues were immediately frozen and stored at -80°C prior to extraction of peptides and RNA.

Peptide Extraction and Radioimmunoassay

Tissues were extracted as reported previously

Results

UCN-LI was detected in every region of brain examined (Fig. 1 A), including the hypothalamus (3.13 ± 0.35 pmol/g wet weight, n = 6), pons (2.79 ± 0.44 pmol/g wet weight), and frontal cortex (3.10 ± 0.24 pmol/g wet weight). The concentrations of UCN-LI in the human brain were approximately 3 pmol/g wet weight in any region of brain, and no marked regional difference was noted [F(8, 45) = 0.141; p > 0.1]. On the other hand, the highest concentrations of CRH-LI were found in the frontal cortex

Discussion

The present study has shown the presence of UCN-LI and the expression of UCN mRNA in the human brain. In contrast to the regional distribution of CRH, no marked regional difference was noted in the regional distribution of UCN-LI in the human brain.

The chromatographic analyses of the human brain extracts using Sephadex G50 column showed at least two peaks in addition to a peak eluting in the position of UCN. A peak eluting in the smaller weight region may represent a fragment of UCN. The

Acknowledgements

We are grateful to K. Kikuchi for her excellent technical assistance. This study has been supported partly by a research grant for medical science from the Nippon University Alumni Association (to M. S.), a Grant-in-aid for Scientific Research (C; No. 09670117) from the Ministry of Education, Science, Sports and Culture of Japan (to K. T.), a Grant-in-aid for the Brain Science Research from the Ministry of Health and Welfare of Japan (to K. T.), and by the Gonryou Medical Foundation (to K. T.).

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