thus , the extracellular calcium-deprivation in t51b rat liver cells in culture which induces a late g-1 block is rapidly reversible ( cells surge into s phase within one hour ) either by creating a cyclic amp surge by the addition of calcium or 3-isobutyl-1-methyl xanthine ( a cyclic 3',5'-nucleotide phosphodiesterase inhibitor ) or by the exogenous addition of low concentrations of cyclic amp itself ( i.e. , 10 ( -8 ) -10 ( -5 ) m ) .
C0007634
cells
C0080129
s phase