112 SHAINKIN-KERSTENBAUM ET AL.
response was found between the two groups. The 1/G molar 15. Neligan, G. A., Robson, E., and Watson, J .: Hypoglycemia in the newborn, a ratio, low during fasting, rose significantly after stimulation in sequel of intrauterine malnutrition. Lancet, i: 1282 (1963). 16. Reissner, S. N., Aranda, J. V., Colle, E .. Papageorgiou, A .. Schiff, D., both groups. Scriver. C. R .. and Stern, L: The effect of intravenous glucagon on amino We have demonstrated that pancreatic endocrine activity is acids in the newborn. Pcdiat. Rc6., 7: 184 (1973). the same at birth in both SGA and AGA infants and is adequate 17. Ruiton-Ugliengo, A., and Frederich, F.: Dosage radio-immunologique speci to the metabolic state in neonatal life. fique du glucagon pancreatique: Applications chez le nouveau-ne et l'enfant. Diahcte Metahol., 1: 143 (1975). 18. Salle, B., Chance, G. W .. and Ruiton-Ugliengo, A.: In: J. Stetson and P.R. REFERENCES AND NOTES Swyer: Neonatal Intensive Care, p. lh5 (Warren H. Green, St. Louis, Mo., I. Adams, P. A. J.: Control of glucose metabolism in the human fetus and the 1900). newborn infant. Advan. Metabol. Disord., 5: 184 (1971). 19. Salle. B .. and Ruiton-Ugliengo, A.: Glucose disappearance rate, insulin 2. Anthony, L. E., and Faloona, G. R.: Plasma insulin and glucagon levels in response and growth hormone response in the small for gestational age and protein malnourished rats. Metabolism, 23: 303 (1974). premature infants of very low birth weight. Biol. Neonate, 29: l ( 1975). 3. Assan, R.: In vivo metabolism of glucagun. In: P. J. Lefebvre and R. H. 20. Samols, J. K., Tyler, J.M., and Marks, V.: Glucagon-insulin interrelation Unger: Glucagon, Vol. 47 (Pergamon Press, New York, 1972) .. ships. In: P. J. Lefebvre and R.H. Unger: Glucagon, Vol. 151 (Pergamon 4. Cornblath. M., Wybregt, S.'H., Baens, G. S., and Klein. R. I.: Sympto Press, New York, 1972). matic neonatal hypoglycemia: Studies of carbohydrate metabolism in the 21. Sperling. M.A .. Delamater, P. V .. Phelps, D., Fiser, R. J. R., Oh, W., and newborn infants. Pediatrics, 33: 388 (1964 ). Fischer, D. A.: Spontaneous and amino-acid stimulated glucagon secretion 5. Delamater, P. V., Sperling, M.A., Fiser R. M., Phelps D. L., Oh. W., and in the intermediate post-natal period: Relation to glucose and insulin. J. Fischer D. A.: Plasma alanine relation to plasma glucose, glucagon and Clin. Invest. 53: I 159 (1974). insulin in the neonate. J. Pediat., 85: 702 (1974). 22. Unger, R.H.: Glucagon physiology and pathophysiology. N. Engl. J. Med., 6. Extern, J.M.: Gluconeogenesis. Metabolism, 21: 945 (1972). 285: 443 (1971). 7. Falorni, A., Massi-Benedetti, F., Gallo, S., and Romizi. S.: Levels of glucose 23. Unger, R. H.: Alpha and hcta cell interrelationships in health and disease. in blood and insulin in plasma and glucagon response to arginine infusion in Metaholism,23: 581 (1974). low birth weight infants. Pediat. Res .. 9: 55 (1975). 24. Unger, R.H., and Lefebvre, P. J.: Glucagon physiology. In: P. J. Lefebvre 8. Falorni, A .. Massi-Benedetti, F .. Gallo, S .. and Trabalza, N .: Blood glucose, and R. H. Unger, Glucagun, Vol. 4 7 (Pergamon Press, New York, 1972). serum insulin, and glucagon response to arginine in premature infants. Biol. 25. Williams. P.R .. Fiser. R.H., Sperling, M.A., and Oh, W.: Effects of oral Neonate,27: 271 (1975). alanine feeding on 0lornJ glucose. plasma glucagon and insulin concentra 9. Hales, C. N., and Randle, P. J.: Immunoassay of insulin with insulin antibody tions in small for gestational age infants. N. Engl. J. Med., 292: 612 (I 975). precipitate. Biochem. J., 88: 13 7 (l 963). 2h. Wisc, J. K., Lyall, S.S., Hendler, R., and Felig, P.: Evidence of stimulation LO. Leroy, B., and Lefort. F.: Courbes de croissancc du nouveau-nc ct du for glucagon secretion by alanine in the human fetus at term. J. Clin. premature Rev. Fran,. Gynecol., 66: 391 (1971). Endocrinol. Metabol., 37: 345 ( 1973). 11. Lubchenko, L. 0 .. and Bard, H.: Incidence of hypoglycemia in newborn 27. Monsieur Biron, Department d'Informatique, Hospices Civils de Lyon. infants classified by birth weigh\ an gestational age. Pediatrics, 47: 831 28. Informed consent was obtained from the parents so that their infants could he (1971). included in this study. 12. Luyck, A. S., Massi-Benedetti, F., Falorni, A., and Lefebvre, P. J.: Presence 29. The authors wish to express their appreciation for advice and for the transla of pancreatic glucagon in the portal plasma of human neonates: Differences tion of Professor P.R. Swyer (Toronto), for the study of results of Professor of insulin and glucagon response lo glucose between normal infants and Bertrand (lnserm, I.yon), for the technical help of Mrs F. Frederich and infants of diabetic mothers. Diabetologia, 8: 296 ( 1972). Mrs. Viand, and for the secretarial assistance of Miss M. Pastor. 13. Massi-Benedetti, F., Falorni, A., Luyck, A., and Lefebvre, P. J .: Inhibition of 30. The present address of Dr. A. Ruiton-Uglicngo is: Unite lnserm U.34 (Pro g1ucagon secretion in the human newborns by simultaneom, administration fessor Bertrand) H6pital Debrousse, 69005 Lyon (France). of glucose insulin. Hormone Metabol. Res., 6: 392 (1974). 31. Requests for reprints should be addressed to: B. L. Salle, M.D., Neonatal 14. Milner, R. D. G., Chouksey, S. K., Micklesow, K. N. P .. and Assan, R.: Department, H6pital Edouard Herriot, 09374 Lyon Cedex 2 (France). Plasma pancreatic glucagon and insulin glucagon ratio at birth. Arch. Dis. 32. Received for publication March 2, 1976. Childhood, 49: 241 (1973). 33. Accepted for publication August h. 1976.
Copyright© 1977 International Pediatric Research Foundation. Inc. Printed in U.S.A.
Pediat. Res. JJ: 112-116 (1977) Cakitonin magnesium calcium parathyroid hormone growth skeletal tissues
Serum Calcitonin and Blood Mineral Interrelationships in Normal Children Aged Six to Twelve Years
RUTH SHAINKIN-KERSTENBAUM. BRURIA FUNK EN STUN. AVIVA CONFORTI. SH RAGA SHANI. AND GEOFFREY M. BERLYNE'""
Department of Nepltrnlogy and "/iwr /nstitwe of Medical Researc/1, Soroka University 1/ospital, Beersheba, Israel
Summary statistically significant rise in serum iTCT levels (r = 0.4638; P < ().01), and a fall in serum iPTH levels (r = 0.4976;P < 0.01). Simultaneous measurements of serum immunoreactive thyro There is a highly significant inverse correlation between serum calcitonin (iTCT), immunoreactive parathyroid hormone iTCT and iPTH levels (r = 0.5248; P < U.005). Serum iTCT (iPTH), calcium, inorganic phosphate, magnesium, and alkaline levels were inversely correlated with phosphate levels (r = phosphatase were made in 37 normal children whose ages 0.4989; P < 0.01), the latter being age dependent and falling ranged from 6-12 years. Between the ages of 6 and 12 there is a significantly between the ages of 6 and 12 (r = 0.4802; P < SERUM CALCITONIN AND BLOOD MINERALS 113
(1.00 I). There was no significant relationship between serum µI hypocakitonic scrum were identical so that the same curve calcium levels and iTCT, iPTH, or age. Serum magnesium levels could serve for both volumes of test scrum used. were not correlated with calcium, iTCT, or iPTH levels. Labeling of cakitonin was performed using 10···1 by the method of Hunter and Greenwood (9) with the following modification: oxidation with 20 µI of chloraminc T for 30 sec: separation of Speculation I 1~.-,1] caleitonin from free 1~:,1 was performed by absorption on Scrum rrcr is important in the growth process, particularly in OUSO ( 18) and washing twice with water to remove free ,,.·,1 _ the steady growth towards the end of childhood, and the inverse The labeled hormone was extracted from OUSO with an acid relationship between iTCT and iPTH levels suggests that a dual solution containing 0.25% acetone in 20% acetic acid. The coefficient of variation of replicate determinations was control mechanism exists which is capable of striking the fine 3 .2%. The lower limit of sensitivity of the assav for iTCT was balance between bone anaboli~m and catabolism necessary for 0.2 x IO 111 ng/ml. Scrum iPTH w·as measured-by radioimmu normal skeletal growth. noassay (2) using highly purified bovine PTH and guinea pig antiserum to bovine PTH ( 19). The method of Arnaud (2) was used for radioimmunoassay In childhood scrum phosphorus and calcium levels arc higher with the following mndifications: I 00µ1 and 200 µI scrum were than in adults. and scrum iPTH levels arc lower bctween the incubated with I 00 µI antibody solution. the volume being ages of 6 and 12 than in adults (3. 14. 16). There is little brought to 0.6 ml with barbital saline buffer, 0.05 MpH 7.4. published work on scrum iTCT levels in children. and because of containing I 00 U/ml of Tracylol. After 3 days of prcincubation the accumulated evidence of the importance of TCT in the at 4°. 100 µI labeled 110:,l]PTH (i.e., approximately 2,000 cpm) process of accretion of bone mineral ( I . .'i. IO. I I. 13). it was were added and the reaction mixture was kept at 4° for 4 mnrc decided to investigate scrum iTCT levels in growing. normal days. The reaction was stopped by adding dcxtran-coatcd char children between the ages of 6 and 12. and to correlate them coa I as described above. with other factors of known importance in skeletal metabolism: A standard curve was made by adding to each tube I 00 µI of hypoparathyroid scrum (taken from a patient after total thyro iPTH. calcium, magnesium. phosphorus. and alkaline phospha parathvroidcctomy or after suppressing immunorcactivc PTH by tase. Ca infusion in a volunteer) as a cnntrol for nonspecific interfer e nee caused bv scrum. ANALYTIC METHODS Labeling of PTH was done according to the method of Hunter and Greenwood (9) with the following modification: 60 µI Venous blood was drawn without stasis from normal children chloraminc T were used for 15 sec with termination of the living in Kibbutz Yotvatah in the Aravah Rift Valley of Israel reaction with 4 .8 µI of sodium mctabisulfite. [ 12''l)PTH was who had volunteered for a survey of plasma fluoride levels and absorbed on OUSO and washed twice with water to separate divalent ion studies before a change of water supply to a reverse free 10'·1. Labeled PTH was eluatcd from QUSO in acid solution osmosis system. Adults in the same kibbutz were the control and purified immediately before use on a Bio-Gel P-100 column group. The children were between the ages of 6 and 12. The (20) with elution using an elucnt consisting of HCI in saline blood samples were taken in the forenoon. in the fasting state. in solution. pH 3.2, containing 0.1% human scrum albumin. the height of summer. The blood was placed in a refrigerator at Only two or three tubes of the eluate taken from the peak of 4°. allowed to clot for I yr. and separated at 4°. All the tubes the pure labeled PTH material were used as a tracer in the were made of !lint glass. The blood was then frozen at -20° in subsequent RIA system. The coefficient of variation of replicate several flint glass tubes for each subject and subsequently determinations was 6 .3 % . The lower limit of sensitivity for de thawed once for each test. All samples for scrum iTCT and iPTH termination of iPTH was 0.3 x IO-" g/ml. Plasma levels of 25- assay, respectively. were examined simultaneously with a de hydroxycholccaleiferol (25-HCC) were measured by a protein tailed standard curve being made at the beginning of the test. competitive binding technique (7 ). Standards were also included in each rack of tubes used in the Scrum calcium and magnesium were measured on a Varian radioimmunoassav. Human svnthctic calcitonin (Ciba) and rab atomic absorption spectrophotometer model 1200; inorganic bit antiserum to irnman calciionin ,vcrc kindly donated by Dr. phosphate and alkaline phosphatase were measured on an Au Asher Haymovitz. Rockefeller University. New York. and the toanalvzcr bv standard Tcchnicon methods. Results were ana radioimmunoassay (RIA) for scrum iTCT levels was carried out lyzed hy the ·student I-test and the linear correlation coefficient as follows. was determined on a Hewlett-Packard calculator, model HP 65. A noncquilibrium svstcm was used in 0.1 M phosphate buffer with Hewlett-Packard programs. at pH 7 .5. Scrum samples of I 00 µI and 2 50 µI were incubated with 100 µI antibody solution in buffer containing 0.25% human scrum albumin. Scrum samples without antibodv served as con RESULTS trols. The reaction mixture was brought to a final volume of 0.6 ml with buffer. After 24 hr of prcincubation at 4°. 100 µI (about 2,000 cpm) of labeled cakitonin (freshly labeled or within 2 There werL' 22 mak and 11 frmak children in thl' group weeks of labeling. having been kept frozen at - 20°) was added examined. All were of Ashkcnazi Jewish extraction. to the reaction mixture. Tubes were kept at 4° for another 24 hr. Scrum iTCT levels increased from 0.6 x IO 111 g/ml at age 6 to Separation of bound from free hormone was made using dcx a mean of 3.9 x 10 111 g/ml at age 12. Scrum iTCT incrca~cs tran-coatcd charcoal by the method of Herbert ( 8). with a significantly with age (sec Fig. I). r = 0.51273; P < 0.0 I; scrum modification in the charcoal and dcxtran concentration to a final iPTH falls from 2.9 at age 6 to a mean of I .I at age 12. There is concentration of I% charcoal, 0.25% dcxtran 70 in 0.35% a significant inverse correlation between scrum iPTH levels and human scrum albumin. After adding the charcoal suspension, age (r = 0.4673; P < 0.01) (Fig. 2). tubes were kept at 4° for 40 min to reach equilibrium and then Scrum iTCT and iPTH levels arc highly significantly invcrsel~ were centrifuged. Both supernatant and precipitate radioactivity correlated (r = 0.5621; P< (l.001) (Fig. 3). (It is possible that were measured in a Packard automated gamma counter. the correlation is curvilinear but this has not been statistical!\ A standard curve was made using the same procedure except evaluated in this paper, linear correlation having been found to that each tube contained I 00 µI hypocakitonic scrum obtained be highly significant.) Scrum iTCT levels arc not related to from a patient who had undergone total thyroidcctomy some scrum calcium (r = 0.3438; P < 0.0.'i). magnesium (r = years earlier; this was used to compensate for nonspecific inter 0.0418; P < 0.03). or alkaline phosphatase (r = 0.3790; P ference caused by scrum. Curves which contained 100 µI or 250 < 0 .05). However. there is a significant inverse correlation 114 SHAINKIN-KERSTENBAUM f.T AL.
0 6.
..,; 10 0" 0 0 .. 8 "'0 "' s. 0 "' u 0 0 0 . 0 ...... X 4.8 "' "' .:, 2 · . . • • 4.0 8 10 II 12 13
A 6 E I N Y E A R S 6.0 10 II 12 Fig. I . Relationship between scrum immunorcactivo.: thyrocalcitonin AGE IN YEARS and age in years (r = O.:il273; P < (J.01) . Fig. 4. Relationship of scrum phosphate kvcls correlated with age (r = 0 .48327; /' < (1.01) .
an: significantly correlated with scrum and phosphate (r • • • 0.4074; P < 0.05) and scrum alkaline phosphatase levels (r lE • 0.39395; P < 0.05) . "' In Table I the results arc presented of scrum TCT. PTH. 25- • HCC. calcium . magnesium. :r • phosphate. and alkaline phospha • tasc lcvcls in adults enmparcd with the mean in the 6- 12-year ....X • nld age group. PTH . 25-HCC. calcium. magnesium. phosphate . and alkaline phosphatase levels arc significantly higher in chil
lE • dren. but the TCT level was not significantly different in children and in adults. In Tablc 2 thc mean values of scrum iPTH and • iTCT levels arc prcscntcd in patients grouped according to sex . There arc no significant differences between the series with I • regard to the scrum cunccntrations uf iPTH and iTCT . • • • • 8 10 II 11 13 DISCUSSION A 6 E I N Y E A R S Fig. 2. Relationship between scrum immunorcactivc parathyroid hor There is little publishl·d work on calcitonin levels in childhood mone (PTH) k vcls amt age (r = 0 .4673; /' < (1.01) . after the neonatal period ( 12) and we have onlv been able to find one papcr in whid1 calcitonin levels in the h-12-ycar-old group arc recorded ( 14). They found that. in 65 normal children bctwccn the ages of 5 and 10. 2-1 % had levels of calcitonin 10 greater than the upper limit uf normal in their laboratory for adults of I ng/ml. In the rnursc of a study embracing childhood and adolescence they found that cakitonin levels fell from a mean of about 5 ng./ ml in the first 24 hr uf life to abuut I .5 ng/ml in the I-month to 5-ycar-old age group. and a mean of I ng/ml in thc 5-10-ycar-old age group. Wc found normal adults to be in thcsamcrangcasfoundbyothcrs(l4. 16).i.e .. below Ing/ml. Howcvcr. in the group of 6-12-ycar-old childrcn thcrc was a significant age-dependent risl' in calcitonin levels. frc4ucntly above the levels found in adults. The mean iTCT level of the cntirc age group was found. howl·vcr. to be not significantly different from that in adults. The difference between our find .. ings and those uf Samaan and rnllcagucs ( 14) may be explained as follows: our study presents individual results with age de •: pendence in detail in the 6-12-ycar age group. whereas they 0 published only the means nf sevcral large age groups. concen trating on the difference between the various age groups: i.e. , neonates; I munth-5-vears; 5- 10 vcars; I 0-20 vcars; 21-60 SERUM PTH NGP[R ML years. This method of presentation docs not rcvcai whether the Fig. 3. Relationship between scrum immunorcactive thyrm:alcitonin individual results in a ny one age group showed age dependence ( TCT) and immunorcactive parathyroid hornrnnc ( PTH) le vels (r = whcn considered within the spccifil· group itself. Our finding uf a 0 .5621; I' < (1.001) . calcitonin level which was age dependent ; i.e .. inncasing as the upper end of the age group was approached. is new . It was also between scrum iTCT levels and phusphatc (r = 0 .4268; P< shown that PTH lcvds fall as the age rises from 6- 1 2. and that 0 .05). Scrum phosphate levels arc inversely correlatcd with agc both PTH and TCT levels arc highly significantly correlated . (r = 0.48327; P < 0 .01) (Fig. 4). Scrum iPTH levcls arc not There was no relationship bctwccn scrum calcium levels and significantly correlatcd with scrum calcium levels (r = 0 .00014; scrum PTH or TCT levels; this agrees with the finding of Arnaud P < 0 .2) or scrum magnesium levels (r = 0.0804; P < 0 . 1 ). but <'I al. (3) . who po inted out that scrum PTH levels arc not SERUM CALCITONIN AND BLOOD MINERALS 115
Tabk I . ( ·0111pari.1·011 of111ca11 scrum levels ofi111111u11orrnctii'L ' 1/1_1-ri,calcitu11i11 ( iT( T). i111111111wreactive parathrroid homw11c (i PT/I) , 25-h1·,lrox1·cholecaliji•rol (25-HC(), calcium, 11wg11esiw11, phosphate, and alkaline phosphatase ( Alk-Pasc) in children aged 6-12 and in adults ------~ -- - ·-- ·------· Ca Mg p Alk-Pase . KA ------·- iPTI-I, ng/ml 25-HCC. ng/ml mg/100 ml units/ I 00 ml iTlT. 10 '" g/ml - - - -- ·------Chilur..:n 31 27 II :n 32 18 32 32 x 3 .22 1.98 63.40 10.17 1.77 4.48 25 .00 SD 2 .21 1.30 15 .26 I .07 0 . 16 ±0.51 5 .86 Range 0.2-lJ.8 Adults 30 30 II 30 31 26 30 30 7.SlJ x 2 .hh 0.84 46.lJ4 lJ.71 1.67 3.69 SD I .33 0.592 16.67 0.56 0.24 O.JlJ 5.02 Range 0 .2- 5.4 I I .223lJ7 4.4355 J.332 2 .0813 1.8268 6.771 12 .0734 uf' (,5 61 42 60 60 5lJ 55 I' > 0 . 10 < 0 .0005 < 0 .0025 < 0.025 < !I.OS < 0 .0005 < 0 .0005 . ------·------.. ------·------·--- -- I Degrees of freedom.
Ta hie 2. !Jfect of.H'X ofchildren 011 i111111wwn•actin· parathrroit! cloudless skies. They were also significantly higher than the hur111011c (il'Tfl) a11t! i111111111wrcaui1 ·c· thrrornlci1011i11 (iTCT) results found in adults. This may be because children spend more ln·els' of their time with their skin exposed to the sun, e.g .. at the swimming pool. than adults. but this must remain speculation. Plasma iPTH. ng/ml Plasma iTCT. IO '" g/ml Consc4ucntly. the interaction between TCT. PTH. and the most active vitamin D mctabolitics remains to be explored in children Males Females Maks Fcmaks of this age group. Our groups were remarkably uniform with No. 20 I 3 22 13 regard to conditions of life-diet. social and ethnic groups. Mean 1.78 I .'!8 3.27 3.JJ sunlight exposure; all were healthy; all blond samples were taken SD ± 1.31 ± 1. 13 ± I .HI ± 3 .2 on the same day at the height of summer. In contrast. Arnaud's They included hoth white 'P < 0.05. groups were markedly less uniform. and black children, there was a 2-year period of collection of samples. and the children were all sick. It may be suggested that correlated with scrum total calcium levels. but arc correlated our results arc, therefore. possibly more reliable in indicating the with scrum ionized calcium levels. Unfortunately. the design nf changes with age in healthy children in this age group. the experiment in the field 250 km south of this laboratory did not permit the measurement of ionized calcium. On the other hand. the scrum phosphate level is significantly inversely corre CONCLUSION 0 .01) . inversely with scrum TCT (P < lated with age (P < In children from age 6- 12 years. there is an increase in plasma scrum PTH levels (P< 0.05). and this 0.01), and directly with calcitonin levels a nd a decrease in plasma parathyroid hormone between PTH. may indicate a fairly complex interrelationship levels. TCT, and phosphate in this age group . The role of ionized remain speculative in the absence of data. Scrum calcium must REFERE NCES AND NOTES magnesium level was not related to PTH or TCT levels. although it was significantly higher in this age group tha n in adults. I . Alcapoulios. M . A .. Goldha ber. P .. and Munson. P . L.: Thvrocalcitonin tissue cult~re. Science. falling levels of PTH may favor inhibitions of bone resorption induced by PTH in Increasing levels of TCT and 151 : 331 (1966) . mineral accretion in the bone (I. 5) and so contribute to the 2. Arnaud, C. D., Tsau. H. S .. and Litttcdike, T .: The radio-immunoassav of mineralization needed for growth of bone in this age group. The human parathyroid hormone in scrum . J. Clin. Invest .. 50: 21 ( l \171): correlation between scrum T(T and PTH levels is highly signifi J . Arnaud. S. B .. Goldsmith. R. S .. Stickler. G . B .. McCall , J. T .. and Arnaud . nd blood minerals interrelationships in (l.001), and this is possibly mediated hy ionized C. 0 .: Serum parathyroid honnonc a cant ( P < normal children . Pcdiat. Res .. 7: 485 ( 1\17:l) . calcium levels. 4 . Falkner, F.: Some physical growth standards for white North American chil Arnaud et al. (3) found in children of the United States a dren. Pediatrics. l
calci1onin in the mother, neonalc, child, and adult. Amer. J. Obstet. 20. Bio-Rad Laboratory. Richmond, Cal. Gynccol., 121: 622m (1975). 21. Informed consent was obtained from all the subjects and their parents who 15 . Shearns, G., and Warweg. E .: Studies of phosphorus of blood. I. The 100k pan in !his study. pani1ion of phosphorus in whole blood and serum. The serum calcium and 22. G. M. Berlync is an csiablished Investigator of ti,c Chief Scientist's Bureau, plasma phosphatase from birth to maturity. J. Biol. Chem ., 102: 749 Israel Ministry of Health, supported in part by grants from the United (1933). States-Israel Binational Fund and the Israel Ministry of Health. 16. Tashjian, A. H ., Howland, B . G., Melvin, K. W., and Hill, C. S., Jr.: 23. Requests for rcprinls shou!d be addressed to: G. M. Berlyne. M.D .. Professor Immunoassay of human calcitonin. N. Engl. J. Med .. 283: 890 (1970). of Medicine, State University of New York , Chief. Renal Section. Brooklyn 17 . Widdowson, E . M., and Dickerson, J. W. T .: Chemical composition of the Veterans Administration Hospital , 800 Poly Place , Brooklyn. N. Y. 11209 body. In: C. L. Comar and F. Bronner: Mineral Metabolism: An Advanced (USA). Treatise, Vol. 2, Part A, p. 128 (Academic Press. New York . 1964). 24. Received for publication April 19, 197h. 18. Philadelphia Quartz Co .• Philadelphia, Pa . 25 . Accepted for publication August 6, 1976. 19. A gift from Dr. G. Lumb. Manchester Royal Infirmary, Mannheim, England.
Copyright © 1977 lnternalional Pediatric Research Foundali on, Inc . Pri111ed in U.S.A.
Pediat. Res.11:116-119 (1977) Fetus placental transfer
triiodothyronine (T3}
Absence of Placental Tran sfer of L-Triiodothyronine
(T3 ) in the Rat
J . D . DUBOIS, A. CLOUTIER, P . WALKER, AND J. H . DUSSAULT"" Service d'Endocrino/ogie-Metabolisme, Le Centre Hospitalier de /'Universite Laval, Quebec, Canada
Summary the maternal-fetal placental passage of L-triiodothyronine (Ta) is minimal , and that the fetal hypothalamic-pituitary-thyroid To detect placental transfer of L-triiodothyronine (f3 ) in preg axis 25 develops autonomously. However, no clear evidence is available nant rats, we injected 1 µCi (1 l]T3 on the 16th, 18th, and 20th for the autonomy of the fetal hypothalamic-pituitary-thyroid day of gestation. Three hours after the injection, which corre axis in the rat, a species in which this ontogenetic sponds to the equilibrium time determined by a method of maturation occurs during the neonatal period (3 ). constant infusion, the pregnant rats and their fetuses were killed. Many authors have previously reported studies of placental The l'2.'l]T 3 was extracted from the serum or the homogenate by transfer of thyroxine (T ) and Ta in pregnant butanol extractions and alkaline washes. The transfer rate was 4 rats. Some reported 25 a passage of T 4 and T 3 through the placenta (9, 10). whereas calculated from the quantity of l' l]T3 in the serum of the others concluded that T, and T:, could fetuses after 3 hr and from the maternal metabolic clearance rate not reach the fetus ( 4, 13). The methods utilized (8.19 ± 0.45 ml/hr/100 g body weight; mean ± SEM). At the by these authors were indirect methods which were more qualitative 16th day of gestation, the placental transfer of T3 was 0.82 ± than quantitative . They did not measure quantitatively the T or T 0.11 % of the total maternal clearance rate/litter weight; it was 3 4 which reached the fetus. In order to studv placental 1.05 ± 0.25% at the 18th day of gestation and 0.58 ± 0.10% at transfer of T:, we examined T, kinetics in order to ascertain the 20th day of gestation. There were no significant differences the presence or absence of placental transfer of T;, in the rat. between these results. The maternal T3 concentration was 68.27 ± 20.6 ng/100 ml and its production rate was 5.57 ± 0.31 ng/hr/ 100 g; with these data we calculated a maternal-fetal Ta transfer MATERIALS AND METHODS of 46 ± 6 pg/hr. Furthermore, there was no T: transfer observed 1 Virgin Sprague-Dawley rats ( 150-200 g) were mated at the when the mother received 1.9 µg unlabeled T , which 3 led to a supply house (15) and shipped 2 significant rise in maternal T concentration weeks after mating. Pregnant 3 (68.27 ± 20.6 ng to animals were kept in separate 102.23 ± 7 .41 ng/100 cages in a sound-attenuated and ml;P < 0.01 ); there was no detectable T, 0 temperature- and light-controlled room (24 :!: I ; in the fetal serum. From these results we conclude IO hr of that there is darkness, 14 hr of light) and minimal or no placental transfer had free access to rat laboratory of T3 in the rat and that the chow and water. hypothalamic-pituitary-thyroid axis of the fetus develops auton omously. EQUILIBRIUM TIME
Speculation fhc equilibrium time of T, for pregnant rats was calculated by a method of constant infusion. Purified I '~ :, 1IT:i (9µCi/hr, spe The present data plus the fact that the rats are hypothyroid at cific activity: 475 µCi/ µg) was injected through an indwelling birth support the concept of an autonomous development of the jugular cannula for 3 hr at a rate of I .0 cc/hr using hypothalamic-pituitary-thyroid a model 355 axis. It suggests that the rat can syringe pump from Sage Instruments. serve as a useful model for development of this axis in the Blood, 0.5 ml. was collected through a human. carotid cannula at 0, 15. 30. 45. 60, 90, 120, and 180 min after the infusion onset and replaced with an equivalent volume of 0.9% NaCl. The blood samples were centrifuged and the scrum was frozen ( - 20°) until Studies in the sheep (7) and guinea pig ( 11) have shown that cxtra1.:tion. The butanol extraction was performed in duplicates