title: Organ-specific changes in the expression of mannose-6-phosphate receptors during postnatal development in rats.
abstract: The significance of the coexistence of 2 mannose-6-phosphate receptors (MPRs) in most cell types still remains poorly understood. In this study, expression of the cation-dependent MPR (CD-MPR) and the cation-independent MPR (CI-MPR) was measured by Western blot in rat organs at 3 ages, i.e. in newborn and 10- and 90-day-old rats. It was observed that expression of the CI-MPR tends to diminish from newborns to adults in 5 of the 6 organs studied, whereas the CD-MPR did not show a clear tendency over time. In pancreas, conversely, both MPRs increased progressively from newborns to adults. The activity of 2 acid hydrolases was also measured at the different ages, and a low correlation was found with the expression of the 2 MPRs. With the exception of the pancreas, it is possible that the CI-MPR is mostly occupied with the clearance of insulin-like growth factor-II at early stages of development, and that later both MPRs may participate in the maturation of the lysosomal apparatus. We propose that in the pancreas, both receptors may be involved in increasing the proteolytic activity of this exocrine gland during postnatal development.
authors.affiliation: Laboratorio de Biología y Fisiología Celular Dr. Francisco Bertini, Instituto de Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Mendoza, Argentina.
authors.forename: Guillermo F
authors.initials: GF
authors.lastname: Jofré
authors.forename: Valeria
authors.initials: V
authors.lastname: Balmaceda
authors.forename: Tirso
authors.initials: T
authors.lastname: Sartor
authors.forename: Lorena
authors.initials: L
authors.lastname: Carvelli
authors.forename: Patricia
authors.initials: P
authors.lastname: Barrera
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Sosa
mesh_terms: D000375:Aging / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D048788:Growth and Development; D006867:Hydrolases / Q000378:metabolism; D008566:Membranes / Q000201:enzymology; D009928:Organ Specificity; D051381:Rats; D017207:Rats, Sprague-Dawley; D017527:Receptor, IGF Type 2 / Q000378:metabolism*
chemical_list: D017527:Receptor, IGF Type 2; D006867:Hydrolases