Serum thymidine activity and somatomedin-C levels in children and adolescents with Turner's syndrome: effect of chronic estrogen and progestogen replacement therapy.

Turner's syndrome has been used as a model of primary hypogonadism to assess the role of estrogen-progestogen replacement therapy on serum thymidine activity (TA) and somatomedin-C (Sm-C) levels. 33 subjects with gonadal dysgenesis were studied: 10 untreated and 13 treated with estrogen-progestogen combination. In 10 untreated patients serum TA was 1.02 +/- (SEM) 0.04 U/ml and serum Sm-C value was 27.82 +/- 4.14 nmol/l, both similar to those in the age-matched normal children. A positive correlation was found between Sm-C and the bone age (r = 0.891, p less than 0.002). In the 13 treated subjects, the estrogen-progestogen combination as replacement therapy induced a significant increase in Sm-C level (40.52 +/- 4.30 nmol/l, p less than 0.05). No variation was observed for serum thymidine activity between the two groups of subjects.