The hydrocarbons of pig liver

Abstract

CHANNON AND MARRIAN [1926] examined the unsaponifiable fraction of pig liver primarily with a view to investigating the possible presence in liver of the unsaturated hydrocarbon squalene. Their results showed that, although squalene was not present, pig liver contained a highly unsaturated hydrocarbon of apparently very high molecular weight, and some evidence was obtained that this hydrocarbon was of terpenoid nature. The presence of the hydrocarbon was deduced from the ready preparation of an insoluble bromide and of a hydrochloride from fractions of the unsaponifiable matter into which the more unsaturated constituents had been concentrated. Analysis of the former compound showed that it was the bromide of an unsaturated hydrocarbon. The hydrochloride however was contaminated by an impurity which could not be removed and the mean values for the C, H and Cl analyses totalled no more than 98-71 %.The investigation of the unsaturated hydrocarbon did not progress further, because it could not be obtained in pure form; concentrates of it decomposed when distilled in.vacuo, and regeneration by dehalogenation of its halogen compounds was unsatisfactory. Further, deductions as to the molecular formula of the substance from consideration of the analyses of the halogen compounds could not be made, for the molecular weight of the hydrocarbon was unknown, nor could those of the bromide and hydrochloride be determined on account of their properties. The great advances which have been made in knowledge of the chemical nature of the higher terpenes in the last few years and the increasing realisation of the biochemical importance of these substances suggested that further investigation of the liver compound was desirable. It seemed not inconceivable that this compound might be concerned with the metabolism of carotene and vitamin A, or possibly with that of cholesterol, for the feeding of squalene to rats causes a noteworthy increase in the amount of cholesterol in the liver [Channon, 1926]. This paper therefore contains an account of attempts to obtain the unsaturated hydrocarbon of mammalian liver in pure form as a preliminary to its chemical investigation. Sufficient progress has been made to lead us to publish the results so far obtained, for further advance cannot be made until more material is available, the preparation of which will entail a considerable delay. EXPERIMENTAL.Preparation of the unsaponiftable fraction.Pig liver, having been shown to be richer in the hydrocarbon than that of the other mammals investigated, was again used as the starting material. The method adopted for the preparation of the unsaponifiable matter was essentially that used by Channon and Marrian [1926]. The pig liver was obtained from the

Dolichol: A Naturally-Occurring C100 Isoprenoid Alcohol

“…Channon & Marrian (1926) isolated a compound from the livers of pigs, as well as from livers of other animals, which they considered to be an unsaturated hydrocarbon closely related to squalene. The results of further work led to the conclusion that the compound had the formula C45H76 or C50H84 (Channon, Devine & Loach, 1934).…”

“…Without infrared evidence (or that of nuclear magnetic resonance) it would have been very easy to mistake dolichol for a hydrocarbon, and there was no reason why chemical tests for the presence of a hydroxyl group should have been carried out. Channon et al (1934) purified hepene by chromatography on alumina. It is well known that alumina from different sources may function very differently when used as an adsorbent for chromatography.…”

Between Biochemists and Embryologists – The Biochemical Study of Embryonic Induction in the 1930s

“…Responding to a missive Needham sent while in Germany, Rosenheim wrote that the facts noted in the letter as already discovered warrant the hope that the substance responsible for the effect may be isolated in the near future (Rosenheim, 1933). Harold J. Channon, the Chair of the Biochemical Department at Liverpool University, who focused his research on sterol metabolism in the liver (Channon et al, 1934;Pitt, 2003), sent Needham samples from a liver fractionation he conducted. 6 Marrian sent him samples of sex hormones while Rosenheim and Francis H. Carr, the BDH's director, sent samples of vitamin D analogs.…”

Studies on the nature of the amphibian organization centre IV—Further experiments on the chemistry of the evocator

“…In series C88*/ it was assumed that a sufficient saponification of saponifiable substances would take place in the boiling potash of the Pfliiger method, but in order to ensure this more fully, the ether extract of the glycogen was itself saponified in the later work (series D35&, 3 and 46 b )a s described in an earlier section of this paper. Next to be considered is the unsaponifiable matter of pig liver (Channon, Devine, and Loach, 1934). From Table I it will be seen that most of the activity is in Fraction I, i.e.,the sterol mixture which cryst readily from light petroleum at room temperature.…”

“…(2) Fractionation o f the Total Unsaponifiable Material o f Liver-Our starting-point here was the work of the Liverpool school on the hydro carbons of pig liver, described by Channon, Devine, and Loach (1934). We were provided with actual samples of two of their fractions.…”