Analysis of fat-soluble vitamins. XVI. Antirachitic activity of 5,6-trans-vitamin D3 alone and in the presence of 5,6-cis-vitamin D3 resin, using chick bioassays.

Two biological assays were conducted in which the antirachitic activity in chicks of 5,6-trans-vitamin D3 added to feed is compared with that of 5,6-cis-vitamin D3. On the basis of the results obtained it is concluded that the relative potency of the trans isomer is, at the most, 5% and that the antirachitic activity of the trans isomer is not markedly enhanced (an increase to a relative potency of 16%, at the most) if the cis isomer is also included in the diet. The results are not conclusive on the inhibition or lack of inhibition of the antirachitic activity of 5,6-cis-vitamin D3 by the presence of 5,6-trans-vitamin D3 in the feed.

The toxicity of dimethyl sulphoxide (DMSO) for the dog, pig, rat and rabbit.

Dimethyl sulphoxide (DMSO) was tested for oral toxicity in rats and dogs, and dermal toxicity in rabbits and pigs. Oral administration was by gastric intubation as a 50% equeous solution, 5 days/week at levels equivalent to 9.0, 3.