Energy Metabolism of Erythrocytes in Lambs Chronically Exposed to Fluorine Compounds

Studies were performed to test the effect of environmental fluorine compounds on the energy metabolism of erythrocytes in lambs (Merino × Kent).The concentration of fluorine in serum, ATP, ADP and AMP content in blood and erythrocytes, adenine nucleotide pool (TAN) and adenylate energy charge (AEC) of erythrocytes were determined.A significant decrease in ATP concentration and a significant increase in ADP concentration (p ≤ 0.05) were observed compared to control group.The exposure of lambs to environmental fluorine compounds also caused a significant increase in the content of fluorine in serum.Moreover, a negative linear correlation (r = -0.836) between the erythrocyte ATP concentration and the serum fluorine ion concentration was found.AEC level also correlated linearly (r ≤ -0.949) with the concentration of fluorine ions in serum.These observations suggest that exposure of lambs to environmental fluorine compounds resulted in impaired energy metabolism of their erythrocytes. Adenine nucleotides, adenine nucleotide pool, adenylate energy charge, fluorine, bloodFluorine is known for its exceptional biological activity (Guminska 1994).Chronic environmental exposure of animals to fluorine compounds results in bone fluorosis and accumulation of the element in tendons, articular capsules and muscles (Guminska 1981; Pirog and Socha 2000).The accumulation of fluorine in the body continues during the whole lifespan and constitutes a serious threat to health (Mokrzynski et al. 1994;Chlubek et al. 1994;Machoy 1995).In animals, tenderness of long bone epiphyses, pareses, demineralisation and bone fragility have been observed.Apart from the relatively late anatomical lesions, fluorine is responsible for metabolic disorders in systems, organs, tissues and individual cells (Chlubek et al. 1995; Ignacak and Guminska 1991;Machoy 1995).Fluorine enters the bloodstream through the intestines and lungs.According to Guminska (1990), approx.75% of fluorine appears in plasma, the remaining part in erythrocytes.Apparently, red blood cells possess a special mechanism protecting them against entry or facilitating elimination of fluorine (Korkmaz 2000).Yamamoto et al. (1989) studied the distribution of this element in blood and found that fluorine exists as a free ion, in inorganic and organic compounds.It also binds to plasma proteins, mainly albumin, and as such is biologically inactive (Guminska 1981).Free ions are the active form of fluorine, inhibiting approximately 70 enzymes (Guminska 1994), among them magnesium-dependent transport enzymes (Grabowska et al. 1991; Morris 1992; London and Gabel 1995) and several metabolic pathways (Guminska 1985; Machoy 1987) in red blood cells.Fluorine is a halogen with the lowest mass and ion radius and the highest electronegative potential and reactivity (Wakselman 1999).It may act directly on the enzyme protein, leading to structural changes through disruption of hydrogen bonds, or indirectly by