Evidence that xylosyladenine affects methylation by inhibition of S-adenosyl-L-methionine synthesis.

The adenosine analogs, 9-beta-D-xylofuranosyladenine (XA) and 3'-deoxyadenosine (cordycepin) were tested for their ability to interfer with S-adenosyl-L-methionine (SAM) formation in L1210 cells in vitro. XA inhibited the incorporation of [3H]methionine into SAM in a mixed-competitive manner, while cordycepin was not inhibitory. The adenosine deaminase inhibitor, 2-deoxy-coformycin produced a marked potentiation of the inhibitory effect of XA on Sam synthesis, but did not affect the inactivity of cordycepin.

Measurement of S-adenosyl-L-methionine levels by SP Sephadex chromatography.

Cation-exchange chromatography with sulfopropyl Sephadex was used to measure the levels of S-[methyl-3H]adenosyl-L-methionine synthesized by L1210 cells in vitro. Separation of S-[methyl-3H]adenosyl-L-methionine from [methyl-3H]methionine and other metabolites was achieved by stepwise elution with varying concentrations of HCl.

Potentiation by 2'-deoxycoformycin of the inhibitory effect by 3'-deoxyadenosine (cordycepin) on nuclear RNA synthesis in L1210 cells in vitro.

The effect of the adenosine deaminase inhibitor, 2'-deoxycoformycin, on the inhibitory effect of cordycepin on nuclear RNA synthesis was examined in L1210 cells in vitro. The median inhibitory dose for the effect of deoxycoformycin on adenosine deaminase was 4 X 10(-8) M, and 100% inhibition was achieved at 5 X 10(-7) M. Pretreatment of cells for 30 min with 1 X 10(-6) M deoxycoformycin resulted in a reduction of the median inhibitory dose for cordycepin from 2.

Fate of experimental allogeneically transplanted fetal adrenal glands in nonimmunosuppressed adrenalectomized adult rats.

Long-term survival of allogeneic vascularized fetal adrenal transplants has been demonstrated in adrenalectomized rats. Significant less mortality occurred after adrenalectomy in animals receiving multiple allogeneic fetal transplants compared to nontransplanted rats.