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

  • Mellanby, Edward, Sir, 1884-1955.
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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    produced at some stage in the growth of the infected rye by the direct action of the ultra-violet radiations of sunlight on ergosterol. This mode of origin did not, however, appear very probable because ergot of rye has a dark bluish-black covering and there was doubt as to whether this covering was permeable to the radiations. If it were permeable, then, since ergot contains abundant unactivated ergosterol, exposure of the ergot grains to sunshine ought to increase its calcifying activity. In order to test this point the following experiment was carried out. The effect of irradiating ergot with sunlight and mercury-vapour light. Exp. 6. A sample of whole ergot grains was scattered sparsely over a tin dish and exposed to bright summer sunshine for 12 hours. Another sample was placed on a similar dish and exposed to a mercury-vapour lamp at a distance of about 2 ft. for half an hour. Each sample was then ground and extracted with alcohol. The alcohol was distilled off from each under diminished pressure and the residues were administered to two dogs on an otherwise poor calcifying diet. The third dog received the alcoholic extract of 2 g. untreated ergot. Three puppies of the same litter were given a rickets-producing diet: 1498 received the basal diet plus alcoholic extract of ergot irradiated by sunlight; 1499 received the basal diet plus alcoholic extract of ergot irradiated by mercury-vapour light; 1496 received the basal diet plus alcoholic extract of untreated ergot. Age at beginning: 7 weeks. Duration of experiment: 12 weeks. Basal diet: 80-150 g. white flour, 20 g. separated milk powder, 20 g. lean meat, 10 cc. olive oil, 2-5 g. dried yeast, 3 cc. orange juice, 2-3 g. sodium chloride. Initial Weight at time of X-ray Gain wt. Clinical and radiographic No. of Variations weight (12 wks.) in 12 wks. diagnosis of bone animal in diet g- g- g* condition 1496 Basal diet + untreated ergot (ale. ext. 2 g.) 2430 5300 2870 Bickets similar to 1498 1498 Basal diet + sunlight ergot (ale. ext. 2 g. ergot) 2400 5500 3100 Rickets similar to 1496 1499 Basal diet + Hg-vapour light ergot (ale. ext. 2 g. ergot) 2150 5500 3350 Slight rickets, definitely less than 1496 and 1498 The alcoholic extract of 2 g. only of non-irradiated ergot was given to 1496 so that some degree of rickets should develop, thus allowing the de¬ tection of an increase (if any) in the vitamin D after irradiating ergot by sunlight (1498) and by the mercury-vapour lamp (1499). The results of the experiment show (1) that exposure of intact ergot grains to strong sunlight for 12 hours does not increase their calcifying activity and (2) that exposure to the mercury-vapour lamp for half an hour slightly increases the activity. It is evident that the covering of the ergot grains is relatively impermeable even to very abundant ultra-violet radiations. This result raised some doubt as to whether the presence of vitamin D was due to the direct action of sunlight on the ergosterol present in the ergot. It appeared desirable, then, to decide whether the vitamin D is primarily a product of the sclerotium or whether the rye embryo in which the fungus