Inhibition of calmodulin - regulated calcium pump activity in rat brain by toxaphene

Journal Article · Wed Mar 05 04:00:00 EST 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:7024933

Trottman, C H; Moorthy, K S

In vivo effects of toxaphene on calcium pump activity in rat brain synaptosomes was studied. Male Sprague-Dawley rats were dosed with toxaphene at 0,25,50, and 100 mg/kg/day for 3 days and sacrificed 24 h after last dose. Ca/sup 2 +/-ATPase activity and /sup 45/Ca uptake were determined in brain P/sub 2/ fraction. Toxaphene inhibited both Ca/sup 2 +/-ATPase activity and /sup 45/Ca/sup 2 +/ uptake and the inhibition was dose dependent. Both substrate and Ca/sup 2 +/ activation kinetics of Ca/sup 2 +/-ATPase indicated non-competitive type of inhibition as evidenced by decreased catalytic velocity but not enzyme-substrate affinity. The inhibited Ca/sup 2 +/-ATPase activity and Ca/sup 2 +/ uptake were restored to normal level by exogenously added calmodulin which increased both velocity and affinity. The inhibition of Ca/sup 2 +/-ATPase activity and Ca/sup 2 +/ uptake and restoration by calmodulin suggests that toxaphene may impair active calcium transport mechanisms by decreasing regulator protein calmodulin levels.

• Research Organization: Jackson State Univ., MS
• OSTI ID: 7024933
• Report Number(s): CONF-8604222-
• Journal Information: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Vol. 45:4; ISSN FEPRA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACID ANHYDRASES
AFFINITY
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ANIMAL CELLS
ANIMALS
ATP-ASE
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL EFFECTS
BODY
BRAIN
CALCIUM
CALCIUM 45
CALCIUM ISOTOPES
CENTRAL NERVOUS SYSTEM
DAYS LIVING RADIOISOTOPES
ELEMENTS
ENZYME ACTIVITY
ENZYMES
EVEN-ODD NUCLEI
HYDROLASES
INHIBITION
INSECTICIDES
INTERMEDIATE MASS NUCLEI
ISOTOPES
MAMMALS
MEMBRANE TRANSPORT
METALS
NERVE CELLS
NERVOUS SYSTEM
NUCLEI
ORGANIC COMPOUNDS
ORGANS
PESTICIDES
PHOSPHOHYDROLASES
PROTEINS
RADIOISOTOPES
RATS
RODENTS
SOMATIC CELLS
UPTAKE
VERTEBRATES