Liver microsomes; an integrated morphological and biochemical study.

摘要: Rat liver, liver homogenates, and microsome fractions separated therefrom were examined systematically in the electron microscope sections of OsO 4 -fixed, methacrylate-embedded tissue pellets. It was found that most microsomes are morphologically identical with rough surfaced elements endoplasmic reticula hepatic cells. They appear as isolated, membrane-bound vesicles, tubules, cisternae which contain an apparently homogeneous material noticeable density, bear small, dense particles (100 to 150 A) attached their outer aspect. In solutions various osmolar concentrations they behave like osmometers. The findings suggest derive from reticulum by a generalized pinching-off process rather than mechanical fragmentation. addition relatively few vesicles free particles, probably derived smooth parts reticula. Dense, peribiliary bodies represent minor component same fractions. 1 gm. wet weight pulp contained (averages 10 experiments) 3.09 mg. protein N, 3.46 RNA (RNA/protein N = 1.12), 487 µg. phospholipide P. displayed DPNH-cytochrome c reductase activity alcohol-soluble hemochromogen. preparations proved resistant washing "aging." Treatment versene incubation ribonuclease (30 minutes at 37°C.) resulted appreciable losses partial or total disappearance particles. deoxycholate (0.3 0.5 per cent, pH 7.5) induced clarification suspensions which, upon centrifugation, yielded small pellet conglomerated only occasionally interspersed vesicles. ∼80 90 cent ∼20 original microsomes. supernatant accounted satisfactorily for materials lost during treatment. microsomal is associated whereas nearly all phospholipide, hemochromogen, membrane content