RT Journal Article T1 Seasonal variation of glutathione peroxidase, CK and AST in sheep in a low-selenium region T2 Sezonowe zmiany aktywnosci peroksydazy glutationu, kinazy kreatynowej i transferazy asparaginianowej u owiec z rejonu niedoboru selenu A1 López Alonso, María Marta A1 Miranda Castañón, Marta Inés A1 Hernández Bermúdez, Joaquín A1 Castillo Rodríguez, Cristina A1 Ayala de la Peña, Ignacio A1 Benedito Castellote, José Luis K1 Enzymes K1 Selenium K1 Ewes AB Blood glutathione peroxidase (GSH-Px; E.C. 1.11.1.9) activity, a measure of selenium status, as well as the plasma indicators of muscle damage creatine kinase (CK; E.C. 2.7.3.2) and aspartate aminotransferase (AST; E.C. 2.6.1.1) were evaluated in sheep in a region with low selenium levels during the spring and the summer, because this time may be critical for suffering selenium deficiencies. GSH-Px activity was highest during the spring, when mean values ranged from 74.16 and 90.51 Ul/g Hb, descending drastically during the summer, below physiological levels (P < 0.001) with mean values ranging from 43.33 to 50.01 Ul/g Hb. GSH-Px activity, within the deficiency range, registered during the summer did not originate muscle damage, since the muscle enzymes CK and AST were within their normal range PB Polska Akademia Nauk SN 1230-1388 YR 1997 FD 1997 LK http://hdl.handle.net/10347/24230 UL http://hdl.handle.net/10347/24230 LA eng NO J. Anim. Feed Sci. 1997;6(3):343–351 DS Minerva RD 24 abr 2026