title: Pyroglutamyl peptidase I levels and their left-right distribution in the rat retina and hypothalamus are influenced by light-dark conditions.
abstract: To evaluate the effects of light and darkness on pyroglutamyl peptidase I activity (pGluPI) and its left-right distribution, pGluPI was measured bilaterally in the retina and hypothalamus under selected light-dark schedules. Rats under a 12 h light-dark cycle were divided into four experimental groups. After the end of the 12 h dark period, the animals were kept two additional hours in darkness (group 1), or light (group 2). After the end of the 12 h light period, the animals were kept two additional hours in darkness (group 3), or light (group 4). Experiments were done in light or darkness depending on the 2 h period. In the retina, a previous 12 h light period led to higher values of enzyme activity than dark periods. Left-right predominance, however, depended on the previous 2 h period: the light period led to left predominance, whereas right predominance was found after the 2 h dark period. In the hypothalamus, a left predominance was found only in group 3. These results demonstrate that environmental light conditions influence pGluPI activity in the rat retina and hypothalamus.
authors.affiliation: Department of Physiology, University of the Basque Country, Leioa, Vizcaya, Spain. msanchez@piturda.ujaen.es
authors.forename: B
authors.initials: B
authors.lastname: Sánchez
authors.forename: F
authors.initials: F
authors.lastname: Alba
authors.forename: J D
authors.initials: JD
authors.lastname: Luna
authors.forename: J M
authors.initials: JM
authors.lastname: Martínez
authors.forename: I
authors.initials: I
authors.lastname: Prieto
authors.forename: M
authors.initials: M
authors.lastname: Ramírez
mesh_terms: D000221:Adaptation, Ocular / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D003623:Dark Adaptation / Q000502:physiology*; D007031:Hypothalamus / Q000201:enzymology*; D008297:Male; D011751:Pyroglutamyl-Peptidase I / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000201:enzymology*
chemical_list: D011751:Pyroglutamyl-Peptidase I