Vitamin D in ergot of rye / by Edward Mellanby, Ella Surie, and Douglas Creese Harrison.

  • Edward Mellanby
Date:
[1929?]
Catalogue details

Licence: In copyright

Credit: Vitamin D in ergot of rye / by Edward Mellanby, Ella Surie, and Douglas Creese Harrison. Source: Wellcome Collection.

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    as has been previously shown by E. Mellanby to be the case with wheat germ, contains a rickets-producing factor. The following facts therefore must be taken into account when considering the origin of the vitamin D in ergot. (1) Rye germ and fungi in general contain abundant ergosterol. (2) Rye germ, unaffected by ergot, contains a small amount of activated ergosterol (vitamin D). (3) In the one form of fungus tested (mushrooms) there was no evidence of vitamin D. (4) There is no evidence that the ergosterol in ergotised rye germ can be activated to vitamin D on exposure of the whole grain to direct sunlight. The fact that the experiment with mushrooms gave no evidence of the presence of vitamin D indicates that abundant ergosterol can be present in fungi without any of it being in the form of vitamin D. This is also true of some of the cereals, including oatmeal. On the other hand, although Exp. 7 demonstrates the presence of vitamin D in normal rye germ, the amount present is small as compared with that in the ergot. This suggests that some of the ergosterol in the fungus Claviceps purpurea (ergot) is in the active form. How this ergosterol becomes activated to vitamin D is an unsolved problem. Although at the present time the ultra-violet irradiation of ergo¬ sterol is the only known mode of origin of vitamin D, it is possible that vitamin D can be made from ergosterol by the growing plant independently of ultra-violet radiations. Since vitamin D is found so rarely in nature in any quantity, it is inter¬ esting that ergot should be one of its sources. So far as is known, fish and egg-yolk are the only substances which are powerfully calcifying in their action, other substances like milk, animal fats and meat containing smaller quantities of vitamin D. Some samples of ergot may be roughly estimated to contain about one-eighth to one-quarter the calcifying activity of cod-liver oil. All samples of ergot so far tested, whether of Russian or Spanish origin, are definitely antirachitic. Summary. 1. Ergot of rye is a powerful stimulus to calcification of bone. The factor responsible for this action is soluble in alcohol and ether, resists saponification and has the properties, so far as these are known, of vitamin D. 2. Rye germ itself, unaffected by the ergot fungus Claviceps purpurea, contains a small quantity of calcifying substance which can be extracted by light petroleum. 3. The irradiation of unground ergot grains by strong sunlight produces no increase and the irradiation by the mercury-vapour lamp only a slight increase in the calcifying activity of ergot, although there is abundant ergo¬ sterol present.