Ovary, testis. Freemartins. Accessory generative organs.

Ovary, Testis. Freemartins

MANY years before any androgenic compound was identified and made available in pure form for experiment much had been learned about the biological properties of these hormones by noting the results of castration, transplantation of testes or the injection of testicular extracts. A study of the conditions in which freemartins were produced supplied additional knowledge, and inquiries into the changes in the gonads and accessory genital organs of animals which have a limited breeding season also gave valuable information. Later work with the pure hormones has confirmed and extended the knowledge thus acquired.

Permanent and transient effects. Some of the effects of androgen on the reproductive organs are permanent, others are reversible and endure only while androgen is being supplied in adequate quantity. The permanent effects are produced when growth and sexual development are still incomplete. This does not mean that lasting changes can be brought about only during embryological life, for many organs do not acquire their permanent form and character until long after birth. The gonads become fully differentiated early in embryological existence and afterwards remain relatively immune from permanent injury by androgen. The accessory generative organs complete their development much later and meanwhile their growth and form may be permanently interfered with by androgen. For example, the larynx and the bony pelvis do not acquire their ultimate masculine or feminine conformations until puberty and after; earlier in life they may become permanently deformed under androgenic influence. A few structures, of which the clitoris is an example, appear to remain, even in the adult, susceptible to some degree of permanent metamorphosis when submitted to an excess of androgen, and this seems true also of the facial dermis; for a beard once grown is slow to disappear after the chief sources of androgen have been removed.