Age-, cycle- and topographic dependency of human myometrial prostaglandin (6-keto-PGF1a, PGF2a)-synthesis in vitro

Specimens of human myometrium (isthmus and fundus) freshly obtained at hysterectomy were immediately transferred in ice cold Tyrode solution and placed in superfusion chambers. Spontaneous contractions were recorded, the effluent of the myometrium was analyzed for PGF2a and 6-keto-PGF1a by use of specific radioimmunoassay systems. Dating of the menstrual cycle was achieved by histological evaluation of the endometrium.The PG release rates expressed as ng/min/g wet weight were correlated to the patients age and to the phase of the menstrual cycle. The production rates of 6-keto-PGF1a were negatively correlated to the age of the patients and declined in fundus specimens from 2.89 ± 0.35 ng/min/g wet weight in 39–42 years old patients to 0.52 ± 0.17 ng/min/g wet weight in 48–52 years old women during the secretory phase (p< 0.001). Similar significant correlations were found in specimens obtained from the isthmus uteri.During the proliferative phase fundus specimes produced on average 1.61 ± 0.67 ng/min/g wet weight in 39–42 years old patients and0.49 ± 0.12 n/min/g weight 6-keto-PGF1a in 48–52 years old women respectively (p < 0.001).The PGF2a synthesis in myometrial specimens of fundus or isthmus origin was significantly lower than 6-keto-PGF1a and did not correlate to the age of the patients during the proliferative phase. However, PGF2a release rates during the secretory phase were significantly (p < 0.001) higher in younger women.These results suggest an age-, cycle- and topographic dependency of PGI2 synthesis in human myometrial tissue.