SUPPLEMENTED GAMMA-LINOLENIC ACID AND EICOSAPENTAENOIC ACID INFLUENCEBONE STATUS IN YOUNG MALE-RATS - EFFECTS ON FREE URINARY COLLAGEN CROSS-LINKS, TOTAL URINARY HYDROXYPROLINE, AND BONE CALCIUM CONTENT

The effect of different ratios of the prostaglandin precursors gamma-l inolenic (GLA) and eicosapentaenoic (EPA) acids on bone status in grow ing rats measured as a function of free urinary pyridinium crosslinks and hydroxyproline levels was investigated, Male Sprague-Dawley rats w ere weaned onto an essential fatty acid deficient diet and from their fifth week, different groups of rats received a balanced, semisyntheti c diet, supplemented with different ratios of GLA:EPA supplied as a mi xture of evening primrose oil (EPO) and fish oil (FO), Controls were s upplemented with linoleic (LA; sunflower oil) and alpha-linolenic (ALA ; linseed oil) acids (3:1) or a commercially available rat chow, Anima ls were terminated at 84 days and femur length, ash weight, calcium co ntent, free urinary pyridinium crosslinks (Pyd and Dpyd), total hydrox yproline (Hyp), and creatinine levels measured, Free urinary Pyd and D pyd are good indicators of bone status and they correlated well with H yp. Pyd and Dpyd excretion were significantly decreased in the higher GLA:EPA dietary groups and correlated well (r = 0.7) with Hyp levels, Concomitantly, bone calcium content increased significantly in the sam e dietary groups, These results suggest that diet supplementation with relatively high GLA:EPA ratios are more effective in inhibiting bone resorption than LA:ALA.