Abstract: | The presence of the cyclic nucleotide phosphodiesterase peptide-activator previously isolated from the calf myometrium was studied in uterine tissue of rats at different functional states (in puberty, estrus and diestrus stages, pregnancy) and in human myometrium and myoma. The peptide isolated from calf myometrium, immature rat myometrium and uterine tissue in myoma caused a 3-4-fold stimulation of the phosphodiesterase activity. |