| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1986: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1985: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
We have previously reported that the hypothalamo-pituitary-gonadal axis of male infants transiently activated during the first months of life. As an extension of our work, testosterone(T), dihydrotestosterone(DHT), somatomedin-c(Sm-C),and sex hormone binding globulin binding capacity(SHBG-C) were measured in serum samples, and 5 <alpha> -reductase activity, aromatase activity, DHT-receptor binding, and Sm-C production rate were assayed in cultured human skin fibroblasts obtained from newborn infants, prepubertal boys and male adults.
The following results were obtained. 1. In male infants during first 4 months of age, serum concentration of DHT were as high as those in male adults, and the ratio of DHT/T was significantly high compared to adults(p <0.01). Serum SHBG-C increased in early infancy, but decreased in puberty. 2. There were no agedependent differences in 5 <alpha> -reductase activity and DHT-receptor binding between newborn infants and adults. Aromatase activity was significantly lower in newborn infants and prepubertal boys than in male adults(p < 0.05). 3. The in vitro dissociation rate of DHT-receptor complex in newborn infants was similar to that in adults. 4. Sm-C production rate in fibloblasts was suppressed by T in dose dependent fashion( <10^(-9)> - <10^(-7)> M)
These findings suggest that T and DHT secretion during early infancy play some roles, not on early growth spurt, but on maturation of hypothalamo-pituitary-gonadal unit.
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