Journal of Lipid Research, Vol. 7, 413-421, May 1966
Copyright © 1966 by Lipid Research, Inc.

The intracellular distribution of sterols in Eurycotis floridana and its possible relation to subcellular membrance structures

N. L. Lasser and R. B. Clayton

Department of Chemistry, Harvard University, Cambridge, Massachusetts, and Department of Psychiatry, Stanford University School of Medicine, Palo Alto, California

The roach Eurycotis floridana was reared on a semisynthetic diet containing minimal cholesterol-4-¹⁴C (0.005%) supplemented with cholestanol-7-³H (0.1%), and various tissues of the insect were separated into "nuclear," "mitochondrial," and "microsomal" fractions by differential centrifugation. Muscle and salivary gland were satisfactorily fractionated and results from these are reported together with some, as yet, incomplete results for nerve.

The major concentrations of unesterified sterol and lipid phosphorus were in the mitochondrial and microsomal fractions.

The unesterified sterols of the subcellular fractions were separated by alumina and gas-liquid chromatography. The emergent peaks corresponding to cholesterol, cholestanol, and ⁷-cholestenol (a metabolite of cholestanol) were assayed for ³H and ¹⁴C. No sterol was confined to any one subcellular fraction. The proportions of the three sterols were closely similar in all membranous components of the same tissue, but were different in different tissues.

It is suggested that the different subcellular membrances of a given tissue contain similar repeating structural units in which the individual sterols occupy sterically characteristic spaces.

Supplementary key words roach • muscle • salivary gland • nerve • fractionation • sterols • subcellular distribution • membrane structure • repeating unit

Submitted on October 29, 1965
Accepted on February 11, 1966

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