The significanee of testicular tunetion was shown as
l early as 1849 by Berthold when he observed atrophy of the
comb in castrated cockerels, which could be restored by
implantation of a testis in the abdomen. It was only in
the beginning of the twentieth century, however, that
Bouin and Ancel postulated the formation of certain horrnonal
principles in distinct cell types of the testis. The
identification of testasterene as the biologically active
andregen of the bull testis in 1935 rnarked the beginning
of biochemical studies of testis function. The measurement
of testicular horrnonal products has been difficult for a
long time because only small quantities are produced.
However, present techniques such as radioimmunoassay permit
the measurement of picogram quantities of testosterone4.
Parallel with the development of these techniques,
insight has been gained into the endocrine function of the