title: Renal plasticity in response to feeding in the Burmese python, Python molurus bivittatus.
abstract: Burmese pythons are sit-and-wait predators that are well adapted to go long periods without food, yet subsequently consume and digest single meals that can exceed their body weight. These large feeding events result in a dramatic alkaline tide that is compensated by a hypoventilatory response that normalizes plasma pH; however, little is known regarding how plasma HCO3(-) is lowered in the days post-feeding. The current study demonstrated that Burmese pythons contain the cellular machinery for renal acid-base compensation and actively remodel the kidney to limit HCO3(-) reabsorption in the post-feeding period. After being fed a 25% body weight meal plasma total CO2 was elevated by 1.5-fold after 1 day, but returned to control concentrations by 4 days post-feeding (d pf). Gene expression analysis was used to verify the presence of carbonic anhydrase (CA) II, IV and XIII, Na(+) H(+) exchanger 3 (NHE3), the Na(+) HCO3(-) co-transporter (NBC) and V-type ATPase. CA IV expression was significantly down-regulated at 3 dpf versus fasted controls. This was supported by activity analysis that showed a significant decrease in the amount of GPI-linked CA activity in isolated kidney membranes at 3 dpf versus fasted controls. In addition, V-type ATPase activity was significantly up-regulated at 3 dpf; no change in gene expression was observed. Both CA II and NHE3 expression was up-regulated at 3 dpf, which may be related to post-prandial ion balance. These results suggest that Burmese pythons actively remodel their kidney after feeding, which would in part benefit renal HCO3(-) clearance.
authors.affiliation: Department of Marine Science, University of Texas at Austin, Marine Science Institute, 750 Channel View Drive, Port Aransas, TX 78418, USA. Electronic address: a.esbaugh@austin.utexas.edu.
authors.forename: A J
authors.initials: AJ
authors.lastname: Esbaugh
authors.affiliation: Department of Biological Sciences, University of Alabama, Tuscaloosa, AL 35405, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Secor
authors.affiliation: Division of Marine Biology and Fisheries, University of Miami, Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149, USA.
authors.forename: M
authors.initials: M
authors.lastname: Grosell
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001639:Bicarbonates / Q000097:blood; D017821:Boidae / Q000235:genetics / Q000502:physiology*; D002245:Carbon Dioxide / Q000097:blood; D002256:Carbonic Anhydrases / Q000145:classification / Q000235:genetics / Q000378:metabolism; D004435:Eating / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D015870:Gene Expression; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000145:classification / Q000235:genetics / Q000378:metabolism; D007668:Kidney / Q000378:metabolism / Q000502:physiology*; D008297:Male; D010802:Phylogeny; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D027982:Sodium-Bicarbonate Symporters / Q000235:genetics / Q000378:metabolism; D017923:Sodium-Hydrogen Exchangers / Q000235:genetics / Q000378:metabolism; D013997:Time Factors; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism
chemical_list: D001639:Bicarbonates; D007527:Isoenzymes; D027982:Sodium-Bicarbonate Symporters; D017923:Sodium-Hydrogen Exchangers; D002245:Carbon Dioxide; D025262:Vacuolar Proton-Translocating ATPases; D002256:Carbonic Anhydrases
keywords: Acid–base balance; Alkaline tide; CA IV; Carbonic anhydrase; Kidney; Specific dynamic action; V-type ATPase