Effect of an Acute Maternal Fluoride Dose on Fetal Plasma Fluoride Levels and Enamel Fluoride Uptake in Guinea Pigs

Abstract

We conducted this study to measure maternal plasma, fetal plasma, and fetal enamel fluoride concentrations for four hours following an oral F dose to near-term pregnant guinea pigs. We placed female guinea pigs on de-ionized (Group I) or 3-ppm-F (Group II) drinking water prior to breeding and during gestation. On the 57th day of gestation, we administered a maternal dose of NaF solution (0.6 mg F/kg) by stomach tube. We collected samples of maternal plasma, fetal plasma, and fetal enamel at baseline, at 15 and 30 min, and at one, two, and four h after administration of the dose. We assayed samples for F using a modification of the micro-diffusion and ion-specific electrode method. Group I mean baseline F values were: maternal plasma, 0.016; fetal plasma, 0.002; and fetal enamel, 7.0 ppm. Group II mean values were: 0.055, 0.004, and 19.0 ppm. After the maternal fluoride dose, the mean maternal plasma [F] rose sharply for 30 to 60 min and declined to about 50% of peak values by four h. Fetal plasma [F] changed less in absolute values, but similarly to maternal changes relative to baseline. Fetal enamel mean [F] rose more in Group II than in Group I. Baseline F status had an important effect on F uptake in fetal enamel following an acute maternal fluoride dose.

Osteocalcin and matrix GLA protein in developing teleost teeth: identification of sites of mRNA and protein accumulation at single cell resolution

“…Moreover, BGP immunoreactivity was detected both in enameloblasts and enamel extracellular matrix from teleost fish (this study), rats (Bronckers et al 1994) and humans (Papagerakis et al 2002). Because BGP from teeth is exclusively secreted by odontoblasts and deposited mainly in the dentin, the existence of immunoreactive BGP in enamel may correspond to the migration and/or absorption of serum BGP within this mineralized tissue along its formation and maturation period (Bawden et al 1989). On the other hand, other reports which compare BGP expression in bone and teeth during initial matrix deposition and mineralization in mammals concluded that while in bone no BGP gene expression was detected during initial matrix deposition and mineralization, transcripts encoding BGP could be detected in odontoblasts at the onset of dentin matrix deposition (Sommer et al 1996).…”

Fluoride Concentrations in Human and Rat Bone

“…The bone was dried overnight at llO"C, ashed at 6Oo0C, and pulverized into a fine powder. Up to 1 mg of ash from each sample was assayed using the acid diffusion, ion-specific electrode method originally published by Taves, as modified in our laboratory (8,9). In addition, up to 6 mg of ash was dissolved in acid and assayed according to the method originally published by Singer and Armstrong and used in the NIEHS study (10).…”

Fluoride and Calcium Content of Enamel Organ, Muscle, Liver and Plasma in Rats

“…Plasma and tissue samples were assayed for F using the microdif fusion, ion-specific electrode method originally described by Taves [1968], as modified by and further modified in our laboratory [Bawden et al, 1989]. A significant mod ification incorporated in our method was use of a 10-liter instead of a 70-liter trap.…”

“…This allowed us to increase the concentrations read di rectly by the electrode by an additional 7-fold. Details of the method have been described [Bawden et al, 1989]. The method permitted as say of all samples in the linear part of the standard curve.…”