title: Peritoneal surface area and its permeability in rats.
abstract: OBJECTIVE
  Evaluation of peritoneal surface area and its permeability during dialysis in rats of various ages.
  
  
  METHODS
  Study I: planimetry of peritoneum and its topographic areas was performed in 47 rats of various ages (8-30 weeks). Study II: net ultrafiltration (UF), dialysate-to-serum ratios for urea, creatinine, albumin, and total protein as well as their peritoneal permeability coefficients, were measured during a 1-hour peritoneal exchange with Dianeal 2.5%, in 21 rats of different ages (9-30 weeks) and with various peritoneal surface areas.
  
  
  METHODS
  Male Wistar rats.
  
  
  RESULTS
  The peritoneal surface area in rats increases during aging, but young animals with lower body weight have a relatively larger peritoneal surface area than older, larger animals. The area of the topographic fragments of peritoneum expressed as a percentage of the total peritoneal surface is steady during aging. Efficiency of transperitoneal water removal expressed as net UF per amount of absorbed glucose declines in older animals, with larger peritoneal surface areas. Dialysate/serum ratio of solutes transported from blood to dialysate is proportional to peritoneal surface area. Permeability coefficient (K) of peritoneum to urea and creatinine is unchanged during the aging of animals. However peritoneal permeability (K) to albumin increases during aging, with the opposite tendency for total proteins.
  
  
  CONCLUSIONS
  Kinetics of peritoneal dialysis in rats of different ages is determined by peritoneal surface area and permeability of peritoneum to individual solutes.
authors.affiliation: Department of Pathophysiology, Medical School Poznan, Poland.
authors.forename: M
authors.initials: M
authors.lastname: Kuzlan
authors.forename: K
authors.initials: K
authors.lastname: Pawlaczyk
authors.forename: K
authors.initials: K
authors.lastname: Wieczorowska-Tobis
authors.forename: K
authors.initials: K
authors.lastname: Korybalska
authors.forename: A
authors.initials: A
authors.lastname: Breborowicz
authors.forename: D G
authors.initials: DG
authors.lastname: Oreopoulos
mesh_terms: D000367:Age Factors; D000818:Animals; D001830:Body Surface Area; D001835:Body Weight / Q000502:physiology; D003404:Creatinine / Q000097:blood; D015314:Dialysis Solutions / Q000378:metabolism; D005947:Glucose / Q000493:pharmacokinetics; D008297:Male; D008962:Models, Theoretical; D010530:Peritoneal Dialysis; D010537:Peritoneum / Q000033:anatomy & histology* / Q000737:chemistry*; D010539:Permeability; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012709:Serum Albumin / Q000378:metabolism; D014462:Ultrafiltration; D014508:Urea / Q000097:blood
chemical_list: D015314:Dialysis Solutions; D011506:Proteins; D012709:Serum Albumin; D014508:Urea; D003404:Creatinine; D005947:Glucose