Is inositol (1,3,4,5)-tetrakisphosphate a new second messenger
Hormone-stimulated hydrolysis of inositol (Ins) lipids results in the rapid formation of Ins(1,4,5)P/sub 3/, the second messenger for intracellular Ca/sup 2 +/ mobilization. Recently, a more polar inositol phosphate, Ins(1,3,4,5)P/sub 4/ as well as its probable hydrolysis product Ins(1,3,4)P/sub 3/ have been reported to accumulate in carbachol-stimulated brain slices. Vasopressin addition to hepatocytes prelabeled with (/sup 3/H)-Ins also showed a rapid increase of Ins(1,3,4,5)P/sub 4/, which was similar to that of Ins(1,4,5)P/sub 3/, while the accumulation of Ins(1,3,4)P/sub 3/ was slower. In order to examine whether Ins(1,3,4,5)P/sub 4/ has any functional effects on Ca/sup 2 +/ homeostasis, it was synthesized enzymatically from (/sup 3/H)-Ins(1,4,5)P/sub 3/ using a partially purified phosphoinositol kinase activity from rat brain cortex. (/sup 3/H)-labeled inositol phosphates were separated by anion exchange chromatography and analyzed by HPLC using ammonium formate/phosphoric acid gradient elution. Preliminary experiments indicate that Ins(1,3,4,5)P/sub 4/ up to 10 ..mu..M does not release Ca/sup 2 +/ from vesicular pools in saponin-permeabilized hepatocytes. It has a slight inhibitory effect on Ins(1,4,5)P/sub 3/-induced Ca/sup 2 +/ release. The effect of Ins(1,3,4,5)P/sub 4/ on plasma membrane Ca/sup 2 +/ fluxes are presently being investigated.
- Research Organization:
- Univ. of Pennsylvania School of Medicine, Philadelphia
- OSTI ID:
- 6985827
- Report Number(s):
- CONF-8606151-; TRN: 86-039120
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CALCIUM COMPOUNDS
HOMEOSTASIS
SECRETION
LIPIDS
HYDROLYSIS
PHOSPHATES
BIOSYNTHESIS
PHOSPHOTRANSFERASES
ENZYME ACTIVITY
BRAIN
CATIONS
INOSITOL
ION EXCHANGE CHROMATOGRAPHY
LIQUID COLUMN CHROMATOGRAPHY
LIVER CELLS
RATS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VASOPRESSIN
ALKALINE EARTH METAL COMPOUNDS
ANIMAL CELLS
ANIMALS
BODY
CARBOHYDRATES
CENTRAL NERVOUS SYSTEM
CHARGED PARTICLES
CHEMICAL REACTIONS
CHROMATOGRAPHY
DECOMPOSITION
ENZYMES
HORMONES
INOSITOLS
IONS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LYSIS
MAMMALS
MONOSACCHARIDES
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
PEPTIDE HORMONES
PHOSPHORUS COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
PITUITARY HORMONES
RODENTS
SACCHARIDES
SEPARATION PROCESSES
SOLVOLYSIS
SOMATIC CELLS
SYNTHESIS
TRANSFERASES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques