Nutrition classics. Nature, Volume 244, August 10, 1973: Vitamin D-like action of Solanum malacoxylon on calcium transport by rat intestine. By J.M. O'Donnell and M.W. Smith.

Abstract

A DISEASE of cattle, presenting gross symptoms of calcification of heart, lungs and other tissues, and known as enteque seco in Argentina or as espichamento in Brazil, has been shown to be due to the animals grazing a shrub, Solanum malacoxylon1. Oral administration of the dried leaf of the plant can reproduce the symptoms of the disorder in cattle2. In a study of calcium balance in cattle it was shown that oral dosing with the ground leaf could significantly reverse a negative calcium balance within a few days; the same workers concluded by use of a whole-body counting technique and tracer isotope that the increased retention of calcium was due to greater absorption rather than diminished calcium loss3. The similarity of the clinical symptoms to vitamin D intoxication, taken along with these findings, suggests that the plant leaf may exert an effect on calcium absorption similar to that of vitamin D. We report here a remarkable similarity in action of oral dosing of rats with S. malacoxylon leaf and of vitamin D administration on the initial rates of uptake of calcium by intestinal mucosal preparations.