From owner-metabolic-reg@net.bio.net Wed Oct 25 22:00:00 1995 Path: biosci!bcm.tmc.edu!news.msfc.nasa.gov!elroy.jpl.nasa.gov!swrinde!sdd.hp.com!vixen.cso.uiuc.edu!uwm.edu!msunews!harbinger.cc.monash.edu.au!newshost.anu.edu.au!NewsWatcher!user From: cam@rschp1.anu.edu.au (Cameron Neylon) Newsgroups: bionet.metabolic-reg Subject: Re: Some idle speculation Date: Thu, 26 Oct 1995 17:14:42 +1000 Organization: ANU Lines: 30 Distribution: world Message-ID: References: NNTP-Posting-Host: 150.203.96.61 In article , schlosser@ciit.org (Paul M. Schlosser) wrote: > The main take-home that I got from these is that one should expect purified > enzymes to behave quite differently from in-vivo, and that even microsomal > preps (my bread and butter for the past few years) or "cytosol" are suspect. > Since I'm interested in metabolism and distribution in mammals (including > humans) this is a problematic issue. For the liver, freshly isolated > hepatocytes are then preferred, but there is a fair bit of art/effort to > getting and using them on a regular basis, when sub-cellular preps are > sooooo much easier. sigh And of course even if you are using a system in which the intracellular characteristics are very close to what happens in vivo, then you have to start worrying about the extracellular environment. What effects does taking a fresh hepatocyte out of its usual extra-cellular fluid and putting it in some alien buffer system have? Even disregarding all the magical 'factors' floating around in the ECF how does the difference in fuel concentration affect the cells. The number of studies I've seen where people give cells 10-20mM glucose and expect them to function normally . . . . . . Almost enough to make you want to do a nice simple science like chemistry isn't it? :-) -- Cameron Neylon +61 6 251 1118 (Home) Research School of Chemistry +61 6 249 4181 (Lab) Australian National University or more likely cam@rsc.anu.edu.au .