Distribution of small- and medium-sized molecules within the genital tract of artificially inseminated gilts.

Radiolabelled compounds of different molecular size were used as tracers mixed with seminal plasma to investigate whether seminal plasma enters the oviducts of inseminated gilts. The substances were 125I-labelled human serum albumin for 3 gilts, 131I-labelled polyvinylpyrrolidone plus 59Fe citrate in 2 gilts and 131I-labelled human serum albumin plus 59Fe citrate in 2 gilts. The gilts were slaughtered 1 h after insemination and the radioactivity was measured in 4 parts of the oviduct, 9 parts of the uterine horns, the body of the uterus and the cervix. Different quantities of the compounds used were found in all oviducts, but there was close agreement between the distributions of the two compounds in the genital tract after simultaneous insemination. There was a difference (60-80%) in total amount of recovered radioactivity between left and right uterine horns. It is concluded that all compounds used entered the oviducts regardless of their molecular sizes.