The effects of prostaglandin El [PGE1], testosterone, 17β-estradiol and indomethacin on the zinc flux rate across the jejunal segements isolated from rats of each sex were determined using the Ussing chamber technique. Addition of PGE1 [5.0 μM] to the segment bathing medium significantly stimulated the zinc flux rate from mucosa-to-serosa [J_(ms)] of the jejunal segements isolated from male rats and inhibited it in those from female rats. 17β-estradiol [10 nM] inhibited J_(ms) of jujunal segments isolated from male rats, but testosterone stimulated those from female rats. To confirm that testosterone stimulates and 17β-estradiol inhibits J_(ms), the effects of testosterone on the zinc flux rates of segments isolated from male rats and 17β-estradiol on those from female rats were determined. In those experiments, both testosterone and 17β-estradiol inhibited J_(ms) without affecting the zinc flux rate from serosa-to-mucosa [J_(sm)]. However, when rats were ovariectomized, both of these steroid hormones stimulated J_(ms). Interestingly neither PGE1 nor steroid sex hormones produced any effect on the J_(sm), although indomethacin stimulated the J_(sm) of segments from male rats. These results suggest that steroid sex hormones interact with PGs in influencing the intestinal zinc transport and that endogenous PGs and steroid sex hormones augment the effects of exogenous hormones and PGs.