BODY COMPOSITION AND BONE MARKERS IN WISTAR AND OBESE (ƒÒ) GROWING RATS, FED THE RECOMMENDED DIETARY CALCIUM CONTENT

MAROTTE C; WEISSTAUB A; HERNANDEZ E; GONZALES CHAVES M; PELLEGRINI G; PORTELA ML; ZENI SN

EEUU

Congreso; 31 Annual meeting ASBMR; 2009

ASBMR

Interrelationship between osteoporosis and obesity has been recently described. Therefore, the objective was to compare the effect of feeding a normal calcium diet on body weight and composition and its relation to bone markers levels in Wistar (W) and genetically modified obese (bO) rats during growth. Female W and bO adult rats were mated and fed during pregnancy and lactation diets prepared according to AIN´93 recommendations. At weanling, male pups continued feeding the same diet “ad libitum” till 50 days of age. Food consumption and body weight (BW) were recorded 3times/week. At the end of the experience body composition (AOAC methods), bone alkaline phosphatase (bAP), osteocalcine (BGP) and C-telopeptide of type 1 collagen (CTX) (ELISA) were determined. Results (mean± SD) were:   W (n=11) bG (n=11) p Body water (g/100 g) 64.0 ± 4.6 59.7 ± 2,8 0.02 Body protein (g/100 g) 19.7 ± 2.9 14.9 ± 1.7 0.0012 Body ashes (g/100 g) 3.2 ± 0.4 2.4 ± 0.2 0.0001 Body fat (g/100 g) 10.0 ± 1.7 12.7 ± 3.1 0.0368 bAP (IU/L) 68 ± 10 193 ±  39 <0.0001 BGP (UI/L) 841 ± 106 386 ± 40 <0.0001 SCTX 94 ± 6 65 ± 9 <0.0001 There were no statistical differences in food intake neither in BW. Body composition results indicate an increase in lipogenesis and a decrease in bone ashes content, although there was no differences in the dietary calcium intake. Moreover, the lower BGP and CTX activity in bG would suggest an imbalance in bone metabolism because of a reduction in bone mineralization and bone resorption in spite of the increase in bAP, which reflects the osteoblastic differentiation. Conclusions: These results suggest that the etiology of obesity and osteoporosis should have a biochemical common mechanism. UBACYT (2008-10) B 091.