Abstract
Plasma testosterone in normal subjects and patients with various endocrine disorders has been studied.
A sensitive assay for plasma testosterone was based on the method of competitive protein binding analysis (Maeda et al).
In 113 normal subjects, plasma testosterone levels of five to ten year-old males and females were found to range from 20 to 75ng/dl, and 10 to 50ng/dl, respectively. Normal range of the adult male (age 20 to 70) was between 350 and 1,150ng/dl, and that of the normal female between 27 and 108ng/dl.
Plasma testosterone of a few males over 70 and 80 years of age tended to decrease below 350ng/dl.
Plasma testosterone and 11-OHCS at 8a.m. and 8p.m. were measured in 13 normal males and females, respectively.
In the males, plasma testosterone was high in the morning and low in the evening, which shows a significant diurnal rhythm.
In the females, there was a similar tendency, significance of which is, however, questionable. But adrenal suppression by dexamethasone revealed a difinite presence of the diurnal rhythm of plasma testosterone in the females as well as in the males.
In patients with hypothalamo-pituitary disorders, panhypopituitarism and hypophysectomy, when complete, showed extreme low levels which were even below the normal female range.
High testosterone level of 435ng/dl was demonstrated in a case of male precocious puberty (3 years of age), not suppressible by dexamethasone and responded to HCG stimulation up to 943ng/dl.
In this case, plasma testosterone was diagnostic and proved to be a good index of androgenicity.
Among patients with adrenal disorders, a female with 21-hydroxylase deficiency showed a male-range testosterone level of 546ng/dl, which showed the importance of not only adrenal androgens but also testosterone as a cause of marked virilism. A patient with 17α-hydroxylase deficiency showed a low baseline of 79ng/dl, 170 after ACTH and 144ng/dl after HCG stimulation.
On the basis of these results and other steroid analysis, it was suggested that 17α-hydroxylase was deficient both in testes and adrenals in this case.
Among patients with gonadal disorders, in a complete type of testicular feminization, plasma testosterone was at the normal male level of 537ng/dl, suggesting unresponsiveness of target tissue to testosterone, and decreased to 57ng/dl after resection of intraabdominal testes.
Almost no response to HCG stimulation was observed in 3 cases of Klinefelter's syndrome and one case each of myotonic dystrophy and Werner's syndrome.
In conclusion, plasma testosterone reflects well the function of Leydig cell and seems to be a good index of androgenicity.
It is, therefore, useful in the study of pathophysiology and diagnostic problems of various endocrine disorders.
