Effects of Changes in Hydromineral Balance on Rat Brain Aspartyl, Arginyl, and Alanyl Aminopeptidase Activities

A. Varona; P. F. Silveira; A. Irazusta; A. Valdivia; J. Gil

doi:10.1055/s-2003-38389

Hormone and Metabolic Research, Table of Contents

Horm Metab Res 2003; 35(1): 36-42
DOI: 10.1055/s-2003-38389

Original Clinical

Effects of Changes in Hydromineral Balance on Rat Brain Aspartyl, Arginyl, and Alanyl Aminopeptidase Activities

A. Varona ¹ , P. F. Silveira ³ , A. Irazusta ² , A. Valdivia ¹ , J. Gil ¹

¹ Department of Physiology, Faculty of Medicine, University of the Basque Country, Bilbao, Vizcaya, Spain
² Department of Nursery, Faculty of Medicine, University of the Basque Country, Bilbao, Vizcaya, Spain
³ Laboratory of Pharmacology, Instituto Butantan, São Paulo, Brazil

This study was carried out at the Department of Physiology, Faculty of Medicine, University of the Basque Country.

Abstract

In order to examine the possible relationship between the processing and inactivation roles of aminopeptidases and the disruption of water-electrolyte balance, we measured the activities of aspartyl aminopeptidase (Asp-Ap), arginyl aminopeptidase (Arg-Ap) and alanyl aminopeptidase (Ala-Ap) in certain brain areas (hypothalamus, hippocampus, thalamus and brain cortices) and in the pituitary gland in several models of hydrosaline change. The activity of hypothalamic membrane-bound Asp-Ap significantly decreased (more than 50 %) following treatments which induced a hypovolemic state. Aminopeptidase M activity (membrane-bound Ala-Ap activity with low sensitivity to puromycin) was also significantly decreased by 53 % in the thalamus of rats under conditions of hypovolemia plus hyperosmolality in comparison to the control group. These results indicate that aminopeptidases in the central nervous system may be involved in the physiological regulation of hydromineral balance.

Key words

Peptidase - Neuropeptide Degradation - Osmolality - Water-Electrolyte Homeostasis

Full Text

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J. Gil

Department of Physiology · Faculty of Medicine · University of the Basque Country ·

P.O. Box 699 · 48080 Bilbao · Vizcaya · Spain ·

Phone: + 34 (94) 601-5671 ·

Fax: + 34 (94) 601-5662

Email: ofpgigof@lg.ehu.es