caa a22 4500 465766307 CHVBK 20180323111915.0 cr unu---uuuuu 170327e19900401xx s 000 0 eng 10.1007/BF02535745 doi (NATIONALLICENCE)springer-10.1007/BF02535745 Lipid metabolic interrelationships and phospholipase activity in gustatory epithelium of ictalurus punctatus in vitro [Elektronische Daten] [Joseph Rabinowitz, Taufiqul Huque, Joseph Brand, Douglas Bayley] The catfish,Ictalurus punctatus, is an important model for studying the biochemical mechanisms of taste at the peripheral level. The type, amount and metabolic activity of the lipids within this tissue play important roles in taste transduction by forming the matrix in which the receptors for taste stimuli are imbedded and by acting as precursors to second messengers. The metabolic interconversions that occur among the lipids on the taste organ (barbels) of this animal are reported here. When sodium [32P]phosphate was incubated with minced pieces of epithelium from the taste organ ofI. punctatus, phospholipids became labeled. Maximal incorporation occurred near 20 min for lysophosphatidylcholines (LPC),phosphatidylcholines (PC) and phosphatidylinositols (PI). The phosphatidylethanolamines (PE) and phosphatidylserines (PS) became labeled more slowly. The label in LPC and PC declined from 20 min to 120 min, while that of the other fractions increased or was stable over the 20-120 min time period. Upon addition of 1,2-di-[1′-14C]palmitoyl-sn-glycero-3-phosphocholine to the medium,14C was found within minutes in all of the phospholipids assayed. The amount of label incorporated increased with time, with maximum labeling for all phospholipids occurring at 15 min. However,14C appeared predominantly first (by 5 min) in a neutral lipid fraction (fraction AG, consisting of free fatty acids, mono- and diglycerides, triglycerides and methyl esters), then declined rapidly as the phospholipids gradually incorporated more label. Within minutes of addition of 1-[1′-14C]palmitoyl-sn-glycero-3-phosphocholine (lysophosphatidylcholine) the14C-label was detected in the neutral lipid fraction AG, then in the PC fraction, and later in the other phospholipids. The PC fraction was maximally labeled by 40 min. Using the appropriate radiolabeled substrates, lysophosphatidylcholine phospholipase A1 and phosphatidylcholine phospholipase D activities were detected in this tissue. Very low activity of a phosphatidylcholine phospholipase A2 was observed. The experiments indicate that there are active and rapid exchange, degradation, synthesis and scavenger pathways of phospholipids in the taste organ of this animal, and suggest that phospholipases A1 and D-type activities are primarily responsible for the rapid breakdown of LPC and PC. American Oil Chemists' Society, 1990 Rabinowitz Joseph Veterans Administration Medical Center, University of Pennsylvania, University and Woodland Avenues, 19104, Philadelphia, PA aut Huque Taufiqul Monell Chemical Senses Center, University of Pennsylvania, University and Woodland Avenues, 19104, Philadelphia, PA aut Brand Joseph Veterans Administration Medical Center, University of Pennsylvania, University and Woodland Avenues, 19104, Philadelphia, PA aut Bayley Douglas Monell Chemical Senses Center, University of Pennsylvania, University and Woodland Avenues, 19104, Philadelphia, PA aut Lipids Springer-Verlag 25/4(1990-04-01), 181-186 0024-4201 25:4<181 1990 25 11745 https://doi.org/10.1007/BF02535745 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02535745 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Rabinowitz Joseph Veterans Administration Medical Center, University of Pennsylvania, University and Woodland Avenues, 19104, Philadelphia, PA aut NATIONALLICENCE 700 1- Huque Taufiqul Monell Chemical Senses Center, University of Pennsylvania, University and Woodland Avenues, 19104, Philadelphia, PA aut NATIONALLICENCE 700 1- Brand Joseph Veterans Administration Medical Center, University of Pennsylvania, University and Woodland Avenues, 19104, Philadelphia, PA aut NATIONALLICENCE 700 1- Bayley Douglas Monell Chemical Senses Center, University of Pennsylvania, University and Woodland Avenues, 19104, Philadelphia, PA aut NATIONALLICENCE 773 0- Lipids Springer-Verlag 25/4(1990-04-01), 181-186 0024-4201 25:4<181 1990 25 11745 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer