A radioimmunoassay (RIA) specific for the synthetic 53-70 peptide region of human insulin-like growth factor I (IGF-I) was used to determine IGF-I in the serum of 191 healthy newborns, children and adolescents and in 26 adults. The results compare favourably with reported values obtained using RIA systems for the native IGF-I molecule. Intra- and inter-assay CV were 3.3 and 7.2% respectively. In childhood, mean +/- SD IGF-I levels rise from 6.0 +/- 3.5 nmol/l in newborns to 16.5 +/- 4.0 nmol/l at 8-11 years in both sexes. At the onset of puberty, IGF-I levels in females (24.9 +/- 6.6 nmol/l) are significantly (P greater than 0.005) higher than in males (17.2 +/- 4.2 nmol/l). With further pubertal development IGF-I levels continue to rise, reaching peak values at pubertal stage P4 (40.6 +/- 4.5 nmol/l in males, 42.8 +/- 5.1 nmol/l in females) and decline thereafter to lower values during adulthood: 16.5 +/- 5.8 nmol/l (males) and 24.2 +/- 7.0 nmol/l (females) (P greater than 0.001). In pubertal males, IGF-I correlates significantly with height (r = 0.66, P less than 0.001), bone age (r = 0.69, P less than 0.001) and growth velocity (r = 0.64, P = 0.025) as well as with testosterone levels (r = 0.69, P less than 0.001). In pubertal females a significant correlation is found between IGF-I and height (r = 0.55, P less than 0.020). The ready availability of a simple, precise and reproducible IGF-I RIA, should contribute much to evaluating the importance of IGF-I measurements in normal growth and in the diagnosis and therapy of various growth disorders.
An obese 15-year-old boy of Jewish Iranian origin who is the offspring of consanguineous parents was found to have very low levels of total cortisol in the plasma. Investigation of the family revealed a complete lack of cortisol-binding-globulin (CBG) in the proband and a sister, evidently the first cases of total CBG deficiency to be reported. The parents and a brother were found to have half the normal levels. This study indicates that CBG deficiency, a benign condition, is compatible with a codominant or recessive autosomal trait inheritance.
The levels of beta-endorphin (beta-E) and calcitonin were estimated in 36 samples of seminal plasma from semen of normospermic, oligozoospermic, and azoospermic origins and in pools of isolated sperm. The mean levels in plasma calculated for all samples examined were 192 +/- 224 pg/ml for beta-E and 754 +/- 397 pg/ml for calcitonin. The amounts in sperm were as follows: for beta-E in pools with sperm counts of 0.1-10 x 10(6)/ml, 157.2 +/- 99.7 pg/10(8) and 27.9 +/- 23.6 pg/ml protein; in pools of greater than 10-30 x 10(6)/ml, 71.2 +/- 41.5 pg/10(8) and 6.5 +/- 1.2 pg/mg protein; in pools of greater than 30-200 x 10(6)/ml, 24.9 +/- 9.7 pg/10(8) and 61 +/- 1.9 pg/mg protein. For calcitonin the amounts were: 501.2 +/- 170.8 pg/10(8) and 27.4 +/- 21.5 pg/mg protein, correspondingly. It was suggested that beta-E and calcitonin present in seminal plasma are synthesized mostly in a compartment of the male reproductive system. The high cellular beta-E and calcitonin levels would be involved in the process of motility through their effect on calcium transport.
beta-Endorphin was estimated in normozoospermic, oligozoospermic and azoospermic human semen. The mean amount in normozoospermic specimens was 278.6 +/- 43.6 (SE) pg/ml while in the others only 191.1 +/- 25 pg/ml. Both values are significantly higher than those present in the blood.
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