J Clin Endocrinol Metab 40: 534, 1975
EARLY VARIATIONS OF PLASMA SOMATOMEDIN ACTIVITY IN THE NEWBORN Luciano Tato, Marc V.L. Du Caju, Claude Prevfit, Raphae'l Rappaport. Unite" de Recherche sur les Maladies du Me"tabolisme chez 1'Enfant, Hfipital des Enfants Malades, Paris 75015, FRANCE. ABSTRACT : In neonates, plasma somatomedin as measured by the porcine cartilage assay was very low during the first day of life. A striking increase was observed on day 4 and 5, with a return to lower values at a later age. These findings indicate an early capacity to generate somatomedin activity in newborns. Plasma Sanatomedin (SM) activity has been evaluated previously in pregnant women and in cord blood. During pregnancy Daughaday et al. (1) found SM values in the normal range for adults. At delivery SM in maternal blood was considered to be normal (2) or diminished (3). In cord blood SM was equal or slightly but not significantly lower than in maternal samples (2, 3, 4 ) . In the present study plasma SM activity was measured in normal newborns up to the fifth day of life and compared with values obtained in cord and maternal blood. MATERIAL AND METHODS 25 normal wcmen were studied. Blood samples were drawn in the morning from 11 women between 10 and 40 weeks of gestation and from 14 women at delivery. In the last group corresponding mixed cord blood was collected. 24 normal newboms of both sexes were delivered vaginaly at full term. Birth weights and Apgar scores were normal. They were given a similar diet from the sixth hour of life until the fifth day. All measurements were made on individual samples except during the first day of life where five pools of plasma were prepared, each fron 3 newboms. Finally Submitted November 25th, 1974.
9 infants aged 23 days to 15 months were investigated. The whole study was of the cross sectional type.
The porcine cartilage bioassay was used measuring 35s-sulfate incorporation during 24 hours according to Van den Brande and Du Caju (5). Results were analyzed according to the parallel line assay statistical method described by Finney (6). The mean index of precision (X) was 0.14 in 18 consecutive assays. All values were expressed as potency ratio referring to a plasma pool obtained from five normal adult males. Values of 0.10 or below were considered as not significantly different from undetectable activities. Immunoreactive growth hormone (IRGH) was measured by the double antibody assay (7). The p values for comparison were calculated using a one-tailed student t test or a paired t test. Values equal to 0.10 or below were considered as 0.10 for calculations. RESULTS In pregnant women (n = 11) SM activity ranged from 0.36 to 0.88 with a mean of 0.67 + 0.17 (SD). This was significantly below the normal values for adult males (n = 10) of 1.0 + 0.19 or adult females during the follicular phase of their cycle (n=9) of 0.96 + 0.12 (p < 0.001). At delivery (n = 14) the mean SM was 534
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RAPID COMMUNICATIONS 0.26 + 0.19 (range 0.10 - 0.83) which"was significantly below the values obtained during pregnancy (p < 0.001). These values are in the hypopituitary range (for 9 hypopituitary children, SM activity ranged from 0.10 to 0.26 with a mean of 0.12 + 0.05). In cord (n = 14) the mean SM activity was 0.54 + 0.33 (range 0.101.32). This was significantly (p < 0.01, paired t test) above the corresponding maternal values. In three cases cord SM activities equalling 0.10 or below corresponded to undetectable SM activities in maternal blood (fig. 1). In low-SM maternal and cord plasmas the dose response lines were parallel to the standard pool lines when SM was in the detectable range. In newborns aged from 2 to 10 hours SM was not detectable in 3 individual samples and in 5 pools of plasmas. In three other individual cases, values were respectively 0.14, 0.26, 0.42. The mean SM activity was 0.98 + 0.46 (range 0.43 to 1.55) in six in1 fants aged of 4 to 5 days, and 0.42
.9
11.2
10.8
535
1.6-
I 0.8
§0.6 o
0.4.
0.2
CORD
NEWBORN 2-Whr
NEWBORN 4-5 d
INFANT
Fig. 2 - Plasma SM potency ratio in cord blood, newborns and infants. Open circles indicate plasma pools. For values below 0.10 see fig. 1. + 0.24 (range 0.10 - 0.89) in nine infants aged from 23 days to 15 months. The difference between both groups was significant (p < 0.01) (fig. 2). The mean plasma IPGH concentrations were 30.7 +6.3 (SEM) ng/ml in cord blood, 29.9~+ 12 ng/inl in infants during the first day and 17.3 + 5.0 ng/ml on the 4th and 5th day. After the 23rd day of age, the mean plasma IPGH diminished to 4.1 + 0.8 ng/ml.
§0.6 DISCUSSION
MOTHER
CORD
Fig. 1 - SM potency ratio in paired maternal and cord plasma. Values reported below 0.10 correspondtonondetectable activities.
In normal newborns shortly after birth, the low SM activity contrasted with the high levels of IRGH. This is probably due to a lack of SM generation rather than to the presence of inhibitory substances. We could not demonstrate an inhibitory effect on sulfate uptake in plasmas from cord blood, mothers at delivery or infants with low SM activities by mixing with standard plas-
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JCE & M • 1975 Vol 40 • No 3
RAPID COMMUNICATIONS
536
mas (not shown). Since estrogens have been shown to suppress the growth hormone induced somatomedin activity in vivo (8), the high circulating levels of estradiol at that age may play a major role. However such an explanation holds partly for the results obtained in cord blood since estradiol levels are higher than in newborn blood (9, 10). This may suggest a specific influence of the placenta on circulating somatomedin activity as measured by the present bioassay. In contrast, the sharp increase up to adult values in SM activity on the 4th and 5th day could be explained by the persistence of high levels of IRGH combined with the disapearance of the maternal transfered estrogens as shown previously (9, 10). The significant decrease of SM activities found in infants up to the age of 15 months is in agreement with previous data (11). Although longitudinal data are lacking, it is likely that the decrease of SM activity at one month of age is related to the diitdnution in circulating growth hormone concentration (12, 13). These observations are consistent with the hypothesis that somatomedin generation is active in normal newborns at an early age and that neonatal hormonal changes play a major role in its control.
ACKNOWLEDGMENTS
We are grateful to Prof. E. Papiernik for his cooperation in the Department of Obstetrics, to Dr P. Lazar for statistical evaluation, to Dr P. Czernlchow for performing the radioiitirunoassays and to Mrs G. Lemaire for typing of the manuscript. Supported by fellowships from the Institut National de la Sante" et de la Recherche Meclicale (L.T. and M.D.C.). Reprint request to Dr R. Rappaport.
REFERENCES 1. Daughaday, W.H., W.D. Salmon, and F. Alexander, J Clin Endocrinol Metab 1£ : 743, 1959. 2. Chelsey, L.C., Am J Obstet Gynecol 84^ : 1075, 1962. 3. Hintz, R.L., J.M. Seeds, and R.E. Johnsonbaugh, Pediat Res 8_ : 369, 1974 (Abstract). 4. Andersen, H.J., K.W. Kastrup, and P.E. Lebech, Acta Paediat Scand 62 : 328, 1974 (Abstract). 5. Van den Brande, J.L., and M.V.L. Du Caju, Acta Endocrinol (Kbh) 7!5 : 233, 1974. 6. Finney, D.J., Statistical Method in Biological Assay, ed. 2, Griffin, London, 1964. 7. Schalch, D.S., and M.L. Parker, Nature 203 : 1141, 1964. 8. Wiedemann, E., and E. Schwartz, J Clin Endocrinol 34 : 51, 1972. 9. Kenny, F.M., K. Angsusingha, D. Stinson, and J. Hotchkiss, Pediat Res 2 : 826, 1973. 10. Bidlingmaier, F., M. Wagner-Barnack, 0. Butenandt, and D. Knorr, Pediat Res 1_ : 901, 1973. 11. Van den Brande, J.L., and M.V.L. Du Caju, in Raiti S. (ed), Advances in Human Growth Hormone Research, U.S. Department of Health, Education and Welfare, Washington D.C., 1973, p. 98. 12. Vigneri, R., and R. d'Agata, J Clin Endocrinol Metab 33:561,1971. 13. Cornblath, M., M.L. Parker, S.H. Reisner, A.E. Forbes, and W.H. Daughaday, J Clin Endocrinol 25 : 209, 1965. -~
The Endocrine Society. Downloaded from press.endocrine.org by [${individualUser.displayName}] on 22 November 2015. at 15:10 For personal use only. No other uses without permission. . All rights reserved.
EARLY VARIATIONS OF PLASMA SOMATOMEDIN ACTIVITY IN THE NEWBORN Luciano Tato, Marc V.L. Du Caju, Claude Prevfit, Raphae'l Rappaport. Unite" de Recherche sur les Maladies du Me"tabolisme chez 1'Enfant, Hfipital des Enfants Malades, Paris 75015, FRANCE. ABSTRACT : In neonates, plasma somatomedin as measured by the porcine cartilage assay was very low during the first day of life. A striking increase was observed on day 4 and 5, with a return to lower values at a later age. These findings indicate an early capacity to generate somatomedin activity in newborns. Plasma Sanatomedin (SM) activity has been evaluated previously in pregnant women and in cord blood. During pregnancy Daughaday et al. (1) found SM values in the normal range for adults. At delivery SM in maternal blood was considered to be normal (2) or diminished (3). In cord blood SM was equal or slightly but not significantly lower than in maternal samples (2, 3, 4 ) . In the present study plasma SM activity was measured in normal newborns up to the fifth day of life and compared with values obtained in cord and maternal blood. MATERIAL AND METHODS 25 normal wcmen were studied. Blood samples were drawn in the morning from 11 women between 10 and 40 weeks of gestation and from 14 women at delivery. In the last group corresponding mixed cord blood was collected. 24 normal newboms of both sexes were delivered vaginaly at full term. Birth weights and Apgar scores were normal. They were given a similar diet from the sixth hour of life until the fifth day. All measurements were made on individual samples except during the first day of life where five pools of plasma were prepared, each fron 3 newboms. Finally Submitted November 25th, 1974.
9 infants aged 23 days to 15 months were investigated. The whole study was of the cross sectional type.
The porcine cartilage bioassay was used measuring 35s-sulfate incorporation during 24 hours according to Van den Brande and Du Caju (5). Results were analyzed according to the parallel line assay statistical method described by Finney (6). The mean index of precision (X) was 0.14 in 18 consecutive assays. All values were expressed as potency ratio referring to a plasma pool obtained from five normal adult males. Values of 0.10 or below were considered as not significantly different from undetectable activities. Immunoreactive growth hormone (IRGH) was measured by the double antibody assay (7). The p values for comparison were calculated using a one-tailed student t test or a paired t test. Values equal to 0.10 or below were considered as 0.10 for calculations. RESULTS In pregnant women (n = 11) SM activity ranged from 0.36 to 0.88 with a mean of 0.67 + 0.17 (SD). This was significantly below the normal values for adult males (n = 10) of 1.0 + 0.19 or adult females during the follicular phase of their cycle (n=9) of 0.96 + 0.12 (p < 0.001). At delivery (n = 14) the mean SM was 534
The Endocrine Society. Downloaded from press.endocrine.org by [${individualUser.displayName}] on 22 November 2015. at 15:10 For personal use only. No other uses without permission. . All rights reserved.
RAPID COMMUNICATIONS 0.26 + 0.19 (range 0.10 - 0.83) which"was significantly below the values obtained during pregnancy (p < 0.001). These values are in the hypopituitary range (for 9 hypopituitary children, SM activity ranged from 0.10 to 0.26 with a mean of 0.12 + 0.05). In cord (n = 14) the mean SM activity was 0.54 + 0.33 (range 0.101.32). This was significantly (p < 0.01, paired t test) above the corresponding maternal values. In three cases cord SM activities equalling 0.10 or below corresponded to undetectable SM activities in maternal blood (fig. 1). In low-SM maternal and cord plasmas the dose response lines were parallel to the standard pool lines when SM was in the detectable range. In newborns aged from 2 to 10 hours SM was not detectable in 3 individual samples and in 5 pools of plasmas. In three other individual cases, values were respectively 0.14, 0.26, 0.42. The mean SM activity was 0.98 + 0.46 (range 0.43 to 1.55) in six in1 fants aged of 4 to 5 days, and 0.42
.9
11.2
10.8
535
1.6-
I 0.8
§0.6 o
0.4.
0.2
CORD
NEWBORN 2-Whr
NEWBORN 4-5 d
INFANT
Fig. 2 - Plasma SM potency ratio in cord blood, newborns and infants. Open circles indicate plasma pools. For values below 0.10 see fig. 1. + 0.24 (range 0.10 - 0.89) in nine infants aged from 23 days to 15 months. The difference between both groups was significant (p < 0.01) (fig. 2). The mean plasma IPGH concentrations were 30.7 +6.3 (SEM) ng/ml in cord blood, 29.9~+ 12 ng/inl in infants during the first day and 17.3 + 5.0 ng/ml on the 4th and 5th day. After the 23rd day of age, the mean plasma IPGH diminished to 4.1 + 0.8 ng/ml.
§0.6 DISCUSSION
MOTHER
CORD
Fig. 1 - SM potency ratio in paired maternal and cord plasma. Values reported below 0.10 correspondtonondetectable activities.
In normal newborns shortly after birth, the low SM activity contrasted with the high levels of IRGH. This is probably due to a lack of SM generation rather than to the presence of inhibitory substances. We could not demonstrate an inhibitory effect on sulfate uptake in plasmas from cord blood, mothers at delivery or infants with low SM activities by mixing with standard plas-
The Endocrine Society. Downloaded from press.endocrine.org by [${individualUser.displayName}] on 22 November 2015. at 15:10 For personal use only. No other uses without permission. . All rights reserved.
JCE & M • 1975 Vol 40 • No 3
RAPID COMMUNICATIONS
536
mas (not shown). Since estrogens have been shown to suppress the growth hormone induced somatomedin activity in vivo (8), the high circulating levels of estradiol at that age may play a major role. However such an explanation holds partly for the results obtained in cord blood since estradiol levels are higher than in newborn blood (9, 10). This may suggest a specific influence of the placenta on circulating somatomedin activity as measured by the present bioassay. In contrast, the sharp increase up to adult values in SM activity on the 4th and 5th day could be explained by the persistence of high levels of IRGH combined with the disapearance of the maternal transfered estrogens as shown previously (9, 10). The significant decrease of SM activities found in infants up to the age of 15 months is in agreement with previous data (11). Although longitudinal data are lacking, it is likely that the decrease of SM activity at one month of age is related to the diitdnution in circulating growth hormone concentration (12, 13). These observations are consistent with the hypothesis that somatomedin generation is active in normal newborns at an early age and that neonatal hormonal changes play a major role in its control.
ACKNOWLEDGMENTS
We are grateful to Prof. E. Papiernik for his cooperation in the Department of Obstetrics, to Dr P. Lazar for statistical evaluation, to Dr P. Czernlchow for performing the radioiitirunoassays and to Mrs G. Lemaire for typing of the manuscript. Supported by fellowships from the Institut National de la Sante" et de la Recherche Meclicale (L.T. and M.D.C.). Reprint request to Dr R. Rappaport.
REFERENCES 1. Daughaday, W.H., W.D. Salmon, and F. Alexander, J Clin Endocrinol Metab 1£ : 743, 1959. 2. Chelsey, L.C., Am J Obstet Gynecol 84^ : 1075, 1962. 3. Hintz, R.L., J.M. Seeds, and R.E. Johnsonbaugh, Pediat Res 8_ : 369, 1974 (Abstract). 4. Andersen, H.J., K.W. Kastrup, and P.E. Lebech, Acta Paediat Scand 62 : 328, 1974 (Abstract). 5. Van den Brande, J.L., and M.V.L. Du Caju, Acta Endocrinol (Kbh) 7!5 : 233, 1974. 6. Finney, D.J., Statistical Method in Biological Assay, ed. 2, Griffin, London, 1964. 7. Schalch, D.S., and M.L. Parker, Nature 203 : 1141, 1964. 8. Wiedemann, E., and E. Schwartz, J Clin Endocrinol 34 : 51, 1972. 9. Kenny, F.M., K. Angsusingha, D. Stinson, and J. Hotchkiss, Pediat Res 2 : 826, 1973. 10. Bidlingmaier, F., M. Wagner-Barnack, 0. Butenandt, and D. Knorr, Pediat Res 1_ : 901, 1973. 11. Van den Brande, J.L., and M.V.L. Du Caju, in Raiti S. (ed), Advances in Human Growth Hormone Research, U.S. Department of Health, Education and Welfare, Washington D.C., 1973, p. 98. 12. Vigneri, R., and R. d'Agata, J Clin Endocrinol Metab 33:561,1971. 13. Cornblath, M., M.L. Parker, S.H. Reisner, A.E. Forbes, and W.H. Daughaday, J Clin Endocrinol 25 : 209, 1965. -~
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