Sonographic evidence for the involvement of the utero-ovarian counter-current system in the ovarian control of directed uterine sperm transport

Sperm transport from the cervix into the tube is an important uterine funct ion within the process of reproduction. This functions is exerted by uterin e peristalsis and is controlled by the dominant ovarian structure,ia a casc ade of endocrine events. The uterine peristaltic activity involves only the stratum subvasculare of the myometrium, which exhibits a predominantly cir cular arrangement of muscular fibres that separate at the fundal level into the fibres of the cornua and continue into the circular muscles of the res pective tubes. Since spermatozoa are transported preferentially irate the t ube ipsilateral to the dominant follicle, this asymmetric uterine function may be controlled by the ovary via direct effects utilizing the utero-ovari an counter-current system, in addition to the systemic circulation. To test this possibility the sonographic characteristics of the uterine vascular b ed were studied during different phases of the menstrual cycle. Vaginal son ography with the measurement of Doppler Bow characteristics of both uterine arteries and of the arterial anastomoses of the uterine and ovarian arteri es (junctional vessels) in the cornual region of both sides of the uterus d uring the menstrual phase of regular-cycling women demonstrated significant lower resistance indices of the junctional vessels ipsilateral to the side of the dominant ovarian structure as compared with the corresponding arter ies contralaterally, By the use of the perfusion mode technique, it could b e observed that vascular perfusion of the fundal myometrium was significant ly increased ipsilateral to the dominant follicle during the late follicula r phase of the cycle. These results show that the endocrine control of the dominant ovarian structure over uterine function is not only exerted via th e systemic circulation but also directly, most probably utilizing the utero -ovarian counter-current system.