Cyclic nucleotides in rabbit corneal endothelial cells: Fresh tissue vs. tissue culture

Quantities of adenosine 3′,5′-cyclic monophosphate were measured in rabbit corneal endothelial cells taken from fresh tissue and tissue culture. Higher levels of both nucleotides were observed when the cells were initially frozen in liquid nitrogen compared with those that were not. Adenosine 3′,5′-cyclic monophosphate was 14 times lower in the primary cultures compared to the fresh tissues while subcultures were about two-thirds that of the fresh tissue amount. Guanosine 3′,5′-cyclic monophosphate was four times higher in the primary cultures compared to the fresh tissue while subcultures were about two-thirds that of the fresh tissue amount. It is emphasized that the ratios of adenosine 3′,5′-cyclic monophosphate to guanosine 3′,5′-cyclic monophosphate were similarly high in both fresh tissue and subcultured cells approaching confluency, but quite low in primary outgrowths.