EFFECTS OF DIETARY FLUORIDE AND MAGNESIUM SUPPLEMENTS ON CYCLIC ADENOSINE-MONOPHOSPHATE (CAMP), CALCIUM AND MAGNESIUM LEVELS IN AORTA OF GENETICALLY HYPERCHOLESTEROLEMIC RICO RATS

Previous observations have suggested that low intakes of fluoride prev ent pathological calcifications of internal organs, including the aort ic wall, in experimental animals, fed a basically low magnesium diet. Our group found recently that fluoride has some potentially preventive effect against atherosclerotic serum lipid profiles in genetically hy percholesterolaemic rats. To study whether the apparently positive pot ential of fluoride against atherosclerosis is also reflected in aortic tissue, through its well known activation of adenylate cyclase, the a ortic cAMP content of the rats used in our recent study was determined . Out of a total of 56 male RICO rats, mean weight 160 g, the control group C was fed an adequate diet, with 44% sucrose, a magnesium conten t of 883 p.p.m. and with 0.5% cholesterol. Group D had the same diet a s group C except that the magnesium content was reduced to 200 p.p.m. Group E had the same diet as group D but with the fluoride content ele vated from 1.9 to 12 p.p.m. Group G had the same diet as group E but w ith the magnesium content elevated from 200 to 300 p.p.m. After a feed ing period of 6 weeks, the aortas of the animals were removed, cleaned and kept at -70 degrees C until analysed. The mean cAMP content of th e aortas, measured by radioimmunoassay, in groups C, D, E and G was 43 9, 546, 681, and 1394 mu mol mg(-1) protein, respectively. In group G only, the cAMP content was significantly higher than that of the other groups (p<0.001). The mean calcium and magnesium contents of the aort as of different groups did not significantly differ from each ther. Th us in RICO rats, fed a high-sugar low-magnesium diet with cholesterol, supplementation of the diet with a small amount of fluoride elevates the cAMP content of the aorta, provided that the intake of Mg is not v ery low.