Abstract
In order to determine if plasma SmC levels fluctuate, this peptide was measured (Nichols Institute, San Pedro, CA) at 12 hour intervals (9-10 am,9-10 pm) for 12-48 hours in 18 children (12 boys, 6 girls; 3-18 years) without organic endocrine dysfunction. At consecutive 12 hour intervals [SmC] were:
In this population the mean evening concentration of SmC (0.67 ±.06 U/ml; N=22) was significantly (p <0.01) higher than the morning SmC value (0.46 ±.04 U/ml; N=37). In children with psychosocial deprivation or constitutional delay in growth and development associated with suboptimal nutrition, morning concentrations of SmC were often low, while evening values were normal. In two GH deficient children and one with bioinactive GH, SmC concentrations were low at all times. Diurnal variation in SmC concentrations was not observed in patients with gonadal dysgenesis (N=2) and hypogonadotropic hypogonadism (N=2). Conclusions: 1) There is a diurnal variation in plasma concentrations of SmC; SmC levels are higher at night than in the morning; 2) The diurnal variablity in SmC values may be useful in distinguishing patients with low SmC concentrations not due to hypopituitarism from children with GH deficiency.
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Root, A., Vargas, A. & Livingston, C. 443 DIURNAL VARIATION IN PLASMA CONCENTRATIONS OF SOMATOMEDIN C (SmC) IN CHILDREN. Pediatr Res 15 (Suppl 4), 514 (1981). https://doi.org/10.1203/00006450-198104001-00454
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DOI: https://doi.org/10.1203/00006450-198104001-00454
