Adrenergic control of ova transport and its relation to estrogen

Abstract

Quantitation and cellular location of adrenergic transmitter in the feline oviduct during normal ova transport and exogenous estrogen administration were assessed to determine the possible functional relationship between norepinephrine and estrogen in the control of ova transport. The estrous cycle of 20 mature female cats was monitored by vaginal smears and matings were carefully supervised. Groups of 4 cats each were sacrificed during the following periods of the reproductive cycle: anestrus, estrus, 3 days postcoitally, and 6 days postcoitally. An additional group of 4 cats received estrogen treatment and were sacrificed on day 6 postcoitally. The location of ova in the oviduct was determined by flushing the oviducts and observing the flushings under a dissecting microscope. Ova transport was determined to require 3 to 4 days and exogenous estrogens retard the ova at least until day 6 postcoitally. Fluorescence microscopy was used to determine the distribution of adrenergic terminals in the oviduct. The terminals of the ampulla were observed to be associated primarily with the vessels. In comparison to the ampullar tissue, a more dense adrenergic innervation of the isthmus was noted, and terminals were associated not only with the vessels but also with smooth muscle cells of the muscularis. Terminals were most numerous during the time of ova transport as compared with the anestrous period. Norepinephrine in the ampullae and isthmus was quantitated by ultraviolet spectrophotometry. Norepinephrine concentration was found to correlate positively with periods of estrogen dominance in the isthmus. The results of this experiment suggest an interaction between estrogen and norepinephrine on the mechanism of ova transport.