[The effect of ultraviolet rays and climatic conditions (solar radiation and temperature) on the calcinogenic activity of Trisetum flavescens and Nierembergia veitchii].

Cholecalciferol (Vitamin D3) and its metabolites participate in the regulation of Ca and P metabolism in vertebrates. The intermediate (6,7-cis-precalciferol) is formed by a photoreaction at wave length of 250-310 nm from 7-dehydrocholecalciferol in skin tissues. Vitamin D3, 1,25(OH)2 D3 and other metabolites, previously known to be synthesized only in mammalians and avians, have been detected also in plants. The influence of the UV light (6 hrs radiation with 254 nm) in the calcinogenic activity of T. flavescens and N. veitchii was tested. The extracts of the plants were administered to rachitic chicks in two research models: "Alimentation without Vitamin D" and "Strontium added Alimentation". After 25 days the extracts were administered (per os) and the serum was analyzed to determine the level of Ca, P and alkaline phosphatase. The results were compared with those obtained in chicks with standards of vitamin D3, 1,25(OH)2 D3, T. flavescens and N. veitchii not irradiated and also with T. flavescens that has grown in Rio Grande do Sul/Brazil.