Effects of a high intake of unsaturated and saturated oils on intestinal transference of calcium and calcium mobilization from bone in an ovariectomized rat model of osteoporosis

Abstract

Intestinal transference of calcium and rate of bone turnover were evaluated in ovariectomized rats fed for 15 days with a high amount (30%) of lipid enriched with monounsaturated (groundnut oil), polyunsaturated (sunflower oil) and saturated (coconut oil) fatty acids. The results were compared with those for sham-operated control and ovariectomized groups fed a normal diet (7% groundnut oil). Irrespective of the saturation and unsaturation characteristics, all lipids (edible oils) used in our study considerably decreased the rate of in situ intestinal transference of calcium. Likewise, the activities of intestinal mucosal enzymes, alkaline phosphatase (AP) and calcium ATPase (Ca2+-ATPase) were decreased significantly in all the segments of the small intestine in a descending gradient. Significant changes in bone turnover and bone calcium (Ca) mobilization were confirmed in these animals by marked alterations in plasma AP activity, urinary calcium and phosphate excretion and calcium to creatinine (Ca:creatinine) ratio. Lipid supplementation (30%) in such ovariectomized rats using groundnut oil (monounsaturated), sunflower oil (polyunsaturated) or coconut oil (saturated) for 15 days further enhanced all of the above observed parameters. These results suggest that the intake of high amounts of lipids with different unsaturation and saturation characteristics may be an important factor in determining bone loss in ovariectomized rats.

Black Tea May Be a Prospective Adjunct for Calcium Supplementation to Prevent Early Menopausal Bone Loss in a Rat Model of Osteoporosis

“…Activities of both of these enzymes were found inhibited in ovariectomized group of animals (Table 1). This agrees well with the earlier observations that both enzymes are linked with calcium absorption as the activities of these enzymes correlate with the degree of calcium absorption in different parts of the intestinal tract under different circumstances [29, 47, 48]. BTE supplementation could well restore the activities of both of these enzymes indicating that the observed positive influence of BTE upon intestinal absorption of calcium was possibly mediated through modulation of the activities of these transferring enzymes.…”

Role of oil extract of garlic (Allium sativum Linn.) on intestinal transference of calcium and its possible correlation with preservation of skeletal health in an ovariectomized rat model of osteoporosis

“…Similar to intestinal calcium transference, the activities of both of these enzymes were significantly inhibited in the bilateral ovariectomized rats. This observation finds support from earlier reports that both enzymes are involved in calcium absorption as the activities of these enzymes correlate well with the degree of calcium absorption in different parts of the intestinal tract under different circumstances (Gennari et al, 1984;Chanda et al, 1999 ;Islam et al, 2000). The results of intestinal mucosal enzyme studies therefore suggest that the cause of reduction of calcium transference in ovariectomized animals in our study possibly was due to inhibition of activities of both these enzymes.…”

“…The involvement of two intestinal enzymes alkaline phosphatase and Ca 2+ ATPase, in calcium absorption has been proposed frequently, because the activity of these enzymes correlates with the degree of calcium absorption in different parts of the intestinal tract under different circumstances (Gennari et al, 1984;Chanda et al, 1999;Islam et al, 2000). The activities of both the enzymes are increased by vitamin D (Melancon and De Luca, 1970).…”

Protective Role of Black Tea Extract against Nonalcoholic Steatohepatitis-Induced Skeletal Dysfunction

“…Activities of both of these enzymes were found inhibited in HFD-fed group of animals (Figures 5 and 6). This supports well the earlier observations that both the enzymes are involved in calcium absorption as the activities of these enzymes correlate with the degree of calcium absorption in different parts of the intestinal tract under different circumstances [50, 71, 72]. BTE supplementation could well restore the activities of both of these enzymes indicating that the observed positive influence of BTE upon intestinal transference of calcium is thus mediated through modulation of activities of these transferring enzymes.…”

“…The involvement of two intestinal enzymes, alkaline phosphatase, and Ca 2+ -ATPase, has been proposed frequently in this phenomenon because the activity of these enzymes correlates with the degree of calcium absorption in different parts of intestinal tract under different circumstances [50, 71, 72]. Results also indicate that Ca 2+ -induced ATP hydrolysis in the intestine is the result of two enzymatic activities, namely, alkaline phosphatase present in brush border as well as basolateral membranes and a more specific Ca 2+ -ATPase exclusively located in basolateral plasma membrane [73].…”