Influence of coffee on fluoride metabolism in rats.

Concomitant intragastric administration of sodium fluoride and coffee resulted in a significantly higher (P less than 0.01) plasma fluoride level than intake of the same amount of fluoride with water. The same result was obtained when coffee was substituted with an equivalent amount of caffeine. Comparison of plasma fluoride levels by total area under the curve of plasma fluoride concentration versus time indicated an almost 2-fold difference. Although the mechanism(s) is not known, it appears that caffeine is responsible for the present observation. This finding could help explain the variations in the incidence of dental fluorosis among people living in optimally fluoridated communities.

The distribution of fluoride of prenatal origin in the rat--a pilot study.

Sixteen female, Sprague-Dawley rats were divided into four equal groups. Two groups served as controls receiving low or regular concentrations of fluoride (F); animals in the other two groups were given drinking water, containing 100 parts/10(6) F, for 3 weeks either during or immediately before pregnancy. Thirteen days after delivery, the pups and dams were killed and various tissues analysed for F content. Prenatal F supplementation increased F concentrations in plasma, mandibular incisors and femoral epiphyses of pups by 25, 36 and 38% respectively, when given during pregnancy. Only a slight increase of 9 and 11% in the respective F concentrations of incisors and epiphyses occurred when the supplement was given before pregnancy. The fluoride level of milk was consistently higher than that of the maternal plasma. These results suggest the need for further study of prenatal F supplementation.

Effects of norethynodrel on neoplasms in the buccal pouch of the Syrian hamster.

This study was instituted to determine the effect of a progestin, norethynodrel, on the induction of experimental carcinogens of the hamster cheek pouch. Thirty-six Syrian hamsters were divided into two groups. One group received 2 mg./kg./day of norethynodrel in subcutaneous injections, and the other group received nothing. The right cheek pouches of both groups were painted three times a week with the chemical carcinogen 9,10-dimethyl-1,2-benzanthracene in a 0.05 percent acetone solution. After 9 weeks of painting, the first tumors developed in the hormone-treated hamsters, while none appeared in the control group until after 10 weeks. After 15 weeks, 100 percent of both groups had tumors. The average latent period was 11.8 weeks for the treated group and 12.7 weeks for the control group (p = less than 0.05 percent, Student's test). Norethynodrel significantly decreased the induction time of the neoplasms.