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Levack, Valerie M. (1986) The calcinogenic principles of Trisetum flavescens. Doctoral thesis, City of London Polytechnic.
Studies have been conducted on the calcinogenic plant Trisetum flavescens in order to determine the physiological actions and chemical nature of the toxic substance or substances.
An organic soluble substance was extracted and purified and shown to promote intestinal phosphate transport and increase plasma phosphate levels. This factor was shown to influence the movement of phosphate from the serosa to the bloodstream but not direct uptake from the intestinal lumen. This substance was found to be unlike vitamin D3 or its hydroxy - metabolites in that it did not promote intestinal calcium transport, or bone resorption when studied in vitro. This substance did decrease plasma alkaline phosphatase levels in vitamin D3-deficient chicks however.
An aqueous soluble extract was partially purified on a Sephadex column and found to promote an increase in plasma phosphate in both vitamin D3-replete and vitamin D3-deficient chicks. The extract was also able to Influence intestinal phosphate transport in a similar manner to the organic solvent soluble phosphataemic factor. As both the aqueous soluble and organic solvent soluble factors were active in vitamin D3-deficient chicks they were presumed to act upon the paracellular route for intestinal phosphate uptake. The aqueous soluble factor differed from the organic solvent soluble one in that its administration produced a dramatic decline in the plasma calcium levels of vitamin Do-deficient chicks. The aqueous soluble factor MBS without effect upon bone cultured in vitro.
A second aqueous soluble extract was shown to increase intestinal transport of calcium in chicks with a metabolic deficiency of vitamin D3 caused by the inclusion of strontium in the diet. This substance appears to be able to mimic the actions of 1,25(0H)2cholecalciferol.
The potent aqueous soluble phosphataemic factor is not related chemically to vitamin but has the characteristics of an aromatic indole or amine.
It is concluded that the actions of these three substances in raising plasma [Ca x Pi] results in calcinosis.
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