Characterization by DEAE-cellulose chromatography of a single molecular form of cyclic nucleotide phosphodiesterase in the myometrium of nonpregnant women.

In the longitudinal layer of nonpregnant human myometrium, cyclic nucleotide phosphodiesterase (PDE) activity from the soluble fraction is resolved by DEAE-cellulose chromatography into a single peak which presents no substrate specificity and is calcium-calmodulin-sensitive. As in the homogenate and in the soluble fraction, this peak shows two affinities for cAMP and only one for cGMP. In the soluble fraction of preterm and nearterm myometria, a similar peak is identified, but it presents a biphasic kinetic pattern towards both substrates. During pregnancy, in contrast with the nonpregnant tissue, a second peak of PDE highly selective for cAMP hydrolysis has been isolated specifically in the myometrial soluble fraction. The physiological significance of these two enzymatic forms is still unknown, particularly the role of the cAMP-specific form in the control of uterine motility during pregnancy.