Hepatic prolactin binding in female Sprague-Dawley rats fed a diet high in corn oil.

The relationship between dietary fat content and hepatic prolactin (PRL) binding during the four stages of the estrous cycle was examined. Serum 17 beta-estradiol, PRL, and progesterone were also monitored in the same animals. Female SD rats were fed 5 or 24% corn oil in nutritionally balanced diets, given 2.5 mg 7,12-dimethylbenz[a]anthracene [(DMBA) CAS: 57-97-6] or vehicle by gavage at 8 weeks of age, and decapitated at noon on 1 of the 4 days of the estrous cycle 2-5 weeks later. Analysis of hepatic PRL binding data by Scatchard plots revealed no effect of diet or DMBA. PRL binding was lowest at proestrus, increased at estrus, remained elevated at metestrus, and declined at diestrus. Diet also had no effect on serum hormone concentrations, which showed the expected pattern during the estrous cycle in all treatment groups. Results reported by others of an effect of dietary corn oil content on hepatic PRL binding may have been due to use of control diets low in essential fatty acids.