Distribution of peptidase activity in teleost and rat tissues

Abstract

Peptides play important roles in cell regulation and signaling in many tissues. The actions of peptides are regulated by peptidases. Although the activity of these enzymes has been thoroughly characterized in mammals, little is known about their presence or function in fish. In the present study, we compared the activity of several peptidases in selected tissues (pituitary gland, different brain areas, kidney and gills) of the gilthead sea bream and rainbow trout with that found in similar rat tissues (lungs studied in place of gills). Soluble puromycin-sensitive aminopeptidase showed the highest values in the pituitary gland of the sea bream, whereas the membrane-bound form was found to be more active in the trout kidney. Very high levels of activity of aminopeptidase N were detected in trout and sea bream plasma. In contrast, the highest levels of activity of aminopeptidase B were found in rat tissues, with the exception of the gills of the trout. Aminopeptidase N levels tended to be higher in sea bream tissues with respect to those of trout. In contrast, the level of activity of aminopeptidase B was found to be consistently much higher in trout tissues than in those of the sea bream. Prolyl endopeptidase activity was principally detected in the pituitary gland and in the brain areas of teleosts. These differences between species could be related to different mechanisms of osmoregulation in saltwater- and in freshwater-adapted fish.

Distribution of prolyl oligopeptidase in the mouse whole-body sections and peripheral tissues

“…6. Scale bars a 20 m, b-e 10 m (Daly et al 1985;Fuse et al 1990;Irazusta et al 2002;Agirregoitia et al 2005), there has been a belief that the highest amounts of POP are located in the brain, although the studies have been somewhat inconsistent. The diVerences between these enzyme activity studies may arise from the use of diVerent species and substrates.…”

“…In human and rat tissues, POP enzyme activities have been localized widely in diVerent organs (Kato et al 1980;Daly et al 1985;Fuse et al 1990;Goossens et al 1996;Agirregoitia et al 2005) and high activities have been measured in the brain (Kato et al 1980;Fuse et al 1990;Irazusta et al 2002;Agirregoitia et al 2005). POP-like activity has also been detected in body Xuids (Goossens et al 1996) and in synaptosomal membranes (O'Leary and O'Connor 1995).…”

“…Prolyl oligopeptidase enzyme activities have been previously measured from some peripheral tissues such as skeletal muscle (Daly et al 1985;Fuse et al 1990), testis, liver, kidney, lung, renal cortex and gut (Fuse et al 1990;Goossens et al 1996;Agirregoitia et al 2005). However, the physiological function of POP in peripheral tissues has remained a mystery.…”

Prolyl Endopeptidase Is Involved in Cellular Signalling in Human Neuroblastoma SH-SY5Y Cells

“…These results clearly indicate that the expression of Prep is controlled by RA signalling. Variations in Prep expression have been studied in rodents from their embryonic stage until the animals are aged [35][36][37][38] ; however, the mechanisms involved in the control of this phenomenon have not been elucidated. This is the first result indicating that a specific signalling system, such as RA signalling, modulates PREP expression.…”

Distribution of Immunoreactive Prolyl Oligopeptidase in Human and Rat Brain

“…POP activities have been measured in many brain areas both in humans and rats, including cerebral cortex, hippocampus, cerebellum, hypothalamus and amygdala [5,8,27]. The enzyme activity measurement is a valuable technique to establish distribution, but tissue dissection, homogenization and fractioning are not clear cut and may introduce artefactual variations which may lower the resolution of a distribution map.…”