Document bBq6Bp0rneLqKng8RVwjYdZeZ

AR226-2780 FOR DP PONT OSE ONLY Copies Co: E. I. du Pont de Nemours and Co., Inc. Haskell Laboratory for Toxicology and Industrial Medicine Elkton Road, P. 0. Box 50, Newark, Delaware 19711 HASKELL LABORATORY REPORT NO. 61-82 MR NO. Material Tested Octanolc acid, pentadecafluoro-, ammonium salt (carbonyl C-lshelled) Haskell No. 14,129 Other Codes None Study Initiated/Completed 10/15/81-11/13/81 Material Submitted by Polymer Products Department D-11070 PLACENTAL TRANSFER OF l4C-LABELLED C-8 IN THE RAT Stnsaary: Radioective ^C-labelled perfluorooctanoate (C-8) was transferred fromTmaternal blood to the fetuses of pregnant rats. A single 10 ag/kg dose of T4C-labelled C-8 was administered orally by gavage to the pregnant dams on the 19th day if gestation. Maternal blood and placental levels of II?C-labelled C-8 Increased between 2 and 4 hours after dosing then decreased between 4 and 8 hours after dosing. The p g equivalents of C-labelled C-8 per mL of maternal blood were approximately 12 /g/wT, at 2 hours, 20 pg/mL at 4 hours and 12 jig/mL at 8 hours after dosing. The fetal levels were 0.7 p g/g tissue at 2 hours, 3 p?/g tissue at 4 hours and approximately 3 p g /g tissue at 8 hours after dosing. All other tissues from the pregnant dams were examined for I4C activity and exhibited trends similar to maternal blood, increasing between 2 and 4 hours and decreasing between 4 and 8 hours after dosing. The data reflected only minimal impedence for transfer of ^C-labelled C-8 from maternal blood to the fetuses. Introduction: The study was designed to evaluate placental transfer of ^C-labelled C-8 in the rat. Data regarding placental transfer of C-8 may be useful for evaluating data from teratological studies. Procedures: The 14C-labelled C-8 was obtained from 3M Company as the ammonium salt. The compound was labelled on the carbonyl position and had a specific activity of 0.5 uCi/mg. The compound was 70 percent straight chained C-8 and 30 percent branched isomers. The radiolabelled compound was readily water soluble, therefore wate was used as the dosing vehicle. The dose was formulated immediately prior to dosing. The pregnant female rats 1Company Sanitized. Does not contain TSCA CB/ received a single 10 mg/kg dose of U C-labelled C-8 orally by gavage on the 19th day of gestation. The rats were individually placed in glass metabolism units immediately after dosing. Two rats were sacrificed at each tiae interval of 2, 4, and 8 hours after dosing. Sats were sacrificed by exposure to chlorofora. Blood was drawn by cardiac puncture at sacrifice and refrigerated in heparinized tubes. The placentas, umbilical cords and fetuses were then removed and?dissected from each other and weighed. The umbilical cords and placentas were individually placed into paper combustion cones and fetuses stored frozen. The following organs and tissues were also excised, weighed, and frozen: heart, luc^s, liver, spleen, kidneys, G. I. tract, amnionic sac, hrein, and fat, skin, and The carcasses were also weighed and frozen.. Urine and fecal samples excreted between dosing and sacrifice were collected and frozen. The metabolism units were washed successively with dilute detergent, water, and acetone. The washes were collected and stored in Nalgene* pottles. The placentas, umbilical cords and fetuses were oxidized in their entirety using a Packard Model 306 Sample Oxidizer. Samples of the maternal tissues, carcass and feces were also oxidized and analyzed for activity by liquid scintillation counting with an Intertechnique SL4000 Scintillation Counter. The urine and cage washes were analyzed directly by liquid scintillation counting. f a u l t s : The data in Table 1 were expressed as pg equivalents of C-labelled C-8 per gram wet weight of tissue for the placentas and fetuses. The pg equivalent levels in the placentas increased between the 2- and 4-hour sacrifice points and then decreased between the 4-and 8-hour sacrifice points. The placental values were higher than the corresponding fetal values at each time point, however, the magnitude of the difference was much greater at the 2-hour point than at the 4-and 8-hour points.. The fetal levels were approximately 0.7 p7 equivalents/gram wet weight at the 2-hour point, then increased substantially (4 fold increase) by the 4-hour point to an approximate average value of 3 pg equivalents per gram wet weight. The fetal values remained constant between the 4-and 8-hour points. The number of viable fetuses per animal had no effect on the pg equivalents observed. The average values for the placental and fetal pg equivalents were compared to the corresponding maternal blood values. The data in Table 2 show the maternal pg equivalent levels Increasing-from 14 to approximately 22 ug uivelents/mL between the 2-and 4-hour sacrifice points. The blood le\ s then decreased to approximately 12 p g equivalents/mL between the 4-and 8-hour time points. The most revealing data were the maternal blood/fetal ratios for each animal at the different time points. The ratio dropped substantially from an average of 22 to 8 between the 2-and 4-hour sacrifice points. These data reflected the greater fold increase in the fetal pg equivalent concentrations compared to the increase observed in the maternal blood. The ratio also diminished somewhat between the 4-and 8-hour time points reflecting the decrease in maternal blood levels while fetal levels remained unchanged. 2- Company Sanilfeetf. Da53 no! contain 7SCA CSi ,m fetal aDd Placental p g equivalent .oncentratlona ere also p a r e d In Table 3 to other tissue levels. The kidneys and liver had the highest ag equivalent level regardless of the tlae print. The ug equivalent levels In all tissues and organs tended to Increase between 2 and 4 hours then decreased between 4 and 8 hours. The fetal levels were lower at the 2*hour sacrifice than other tissues presented In Table 3. By the 4-hour sacrifice the fetal concentrations were slailar to the concentrations observed in the spleen, heart, and fat. The fetal levels were stellar to the heart and lungs at the eight-hour sacrifice. The magnitude of the ug equivalent concentration increase was far greater In the fetal tissue than any other organ or tissue examined. Conclusion: Placental transfer of 14C-labelled C-8 was shown to occur after administration of a single oral dose of ^C-labelled C-8. The comparison of fetal levels of C-8 at 2 and 4 hours relative to the concentrations observed In the maternal blood, placenta and other organs revealed evidence of resistance to placental transfer of C-8. However, by 4 hours the fetal concentrations of C-8 Increased substantially more than all other organs and tissues essoined. In contrast to other tissues examined, C-8 levels In the fetuses did not decrease between \ and 8 hours. The peak fetal C-8 concentrations were similar in magnitude to the levels observed In the spleen, heart, lungs and fat. Significant quantities of C-8 can therefore be transferred from the placenta to the fetus with the placental barrier offering minimal resistance to transfer. Synonyms: o Ammonium perfluorooctanoate o C-8 CAS Registry No.: 3825-26-1 -3- Company Sanitized. Does not contain TSCA CBJ Approved by: Ralph W. Harcgrove' U Section Supervisor Biochenical Toxicology SGH:tac:WF:3.2 aDate Issued: May 18, 1982 r ~ ''oRipafiy Sanitized. .*contain TSC A C B TABLE 1 l4C-Labelled C-8 Concentrations in Placentas and Fetuses from Pregnan| Bats Dosed Once Orally with [ C] C-8* Bat# and Time Point Bat #1 2 hours Bat #2 2 hours pg Equivalents Per Gram Wet Weight* Placentas Fetuses (Ave. + S.D.) (Ave. + S.D.) 4.8+0.5(12)" 0.6 + 0.1 (13) 6.1 + 0.3 (4) 0.7 + 0.1 (4) Bat #1 Bat #2 4 hours 4 hours 10.1 + 0.6 (6) 7.0 + 0.5 (8) 3.6 + 0.4 (6) 2.4 + 0.1 (9) fiat #1 Bat #2 8 hours 8 hours 5.1 + 0.6 (11) 4.9 + 0.4 (13) 3.5 + 0.4 (11) 2.5 + 0.2 (13) * ug Equivalents were based on 1.1 x 10^ DPM/mg as the specific i o r i ^ C ] C-8. C activity a Numbers in parentheses Indicate the number of placentas or fetuses. - 5Company Sanitized. Does ro contain TSCA CBf TABLE 2 Coaparisoa of che pg Equivalents of 14 C-Lsbillsd G-B In the Maternal Blood, Placera and Fetus Rat & Tine Point fig Equivalents/g (nL) Maternal Blood Placenta* Fetus Rat 2 hours 14.7 4.8 0.6 Rat #2 2 hours 14.2 6.1 0.7 Maternal Blood/ Fetal Ratio 23 21 Rat #1 4 hours Rat #2 4 hours 25.3 19.4 10.1 7.0 3.6 2.4 7 8 Eat #1 8 hours Rat #2 8 hours 13.4 11.7 5.1 3.5 4.9 2.5 4 5 * The placenta and fetus values are the averages ffon the total nuaber of placentas and fetuses in each anInal. - 6.iQSmJop?aTVf S a n t t i t s -0 C3 -ontain S U A % TABLE 3 Internal Distribution of ^G-Labelied C-8 in Pregnant Fenale Eats Following a Single Oral Dose jig Equivalents [14CJ C-8 Per Lran Wet Weight (a) Tissue 2 Hours Bat fl Bat #2 4 Hours Bat #1 Bat #2 8 Hours Bat #1 Bat #2 Liver 17.5 14.3 21.9 13.3 9.5 8.5 Kidneys 20.2 22.8 40.1 21.2 17.0 14.6 Heart Lungs Skin Spleen 3.9 5.8 3.3 2.0 4.6 5.4 3.7 1.8 5.5 9.8 7.1 3.2 3.9 7.0 4.8 2.0 3.1 2.8 3.9 3.0 2.8 1.9 1.3 1.3 Fat Placenta* 0.9 4.8 1.9 6.1 5.1 10.1 2.0 7.0 2.8 0.6 5.1 4.9 Fetus* 0.6 0.7 3.6 2.4 3.5 2.5 a The jig equivalents were based upon the specific activity of ^C-labelled C-8, 1.1 x 10 DFM/ng. * The values for the placenta and fetus are averages froa the total suaber of placentas and fetuses found in each pregnant rat. 7-