these actions of fsh and gnrha were specific for a plasma membrane phosphodiesterase that was accessible to extracellular camp , since extracellular substrate was hydrolyzed , no intracellular uptake of [ 3h ] camp was observed , and only a small fraction ( 10 % ) of camp was catabolized in the incubation medium in the absence of cells .
C0007603
plasma membrane
C0007634
cells