Serge Voronoff transplanted monkey testicular tissue into a human reproductive gland in 1920. Within five years he had performed the procedure on 300 patients, drawing them from all over the world.[1] In parallel, Eugen Steinach's vasoligation operation — first performed in 1918 — set off a vasectomy boom that ran for two decades.[1]
Neither did anything. Testes used in organotherapy and transplanted for symptoms of hypogonadism, on a large scale, had only placebo effects.[2]
Two competing procedures, one wrong premise
Steinach's vasoligation. Eugen Steinach (1861–1944), a Viennese physiologist, gained worldwide acknowledgement for a theory of "autoplastic" treatment of ageing. His reasoning: tie off the vas deferens, stop the secretory output of the gonads, and the gland would compensate by increasing its incretory — hormonal — production.[1] It is internally logical and rests on a plumbing model of the testis that is simply not how the organ works.
Voronoff's grafts. Serge Voronoff (1866–1951), a Russian working in Paris, went the other way: add tissue rather than redirect it. Monkey testicular tissue, grafted into the human gland.[1]
America had its own versions — Frank Lydston and V. D. Lespinasse performed early human testicular transplantation, and Steinach's vasoligation was taken up by doctors including Harry Benjamin and Charles H. Chetwood.[1]
The patient list is the story
Among those who underwent a rejuvenation operation by Steinach's method were Sigmund Freud and the Irish poet and Nobel laureate William Butler Yeats.[1]
This was not a fringe treatment sold to the credulous. It was taken up by two of the most formidable minds of the century, at the height of their reputations, and it was constantly in the media — Schultheiss and colleagues point to two 1927 caricatures in the German magazine Simplicissimus as evidence of how thoroughly the operations had entered public life.[1]
How it ended
Not with a scandal or a damning trial. From 1935 onwards, rejuvenation operations gradually lost their appeal due to the introduction of artificial androgens.[1]
That is a quietly remarkable sentence. The procedures were not disproved and withdrawn; they were made obsolete. 1935 is the year Ernst Laqueur's Amsterdam group isolated testosterone and Adolf Butenandt and Leopold Ruzicka synthesised it.[2] Once the actual hormone existed in a bottle, the elaborate surgical theories for coaxing more of it out of the body had nothing left to offer.
The story of that year is the year they got the molecule right.
What survives from this era
Two things, and they pull in opposite directions.
The premise was correct. The testes do secrete something that acts at a distance and affects the whole body — established by Berthold's rooster experiment in the previous century. Every one of these practitioners was building on a true foundation.
Being right about the mechanism protected nobody. A correct premise plus an untested intervention produced seventeen years of surgery on an international scale with no benefit. The gap between "this hormone matters" and "this procedure helps" is where the whole era lived.
That gap is still the one that matters. It is why the modern standard is a confirmed diagnosis on repeated fasting morning measurements plus symptoms, rather than a plausible story about hormones — see why one low result doesn't mean low testosterone.
Frequently asked questions
Did the monkey gland transplants actually graft? Whatever happened surgically, the therapeutic result was the same as the rest of organotherapy: placebo.[2] Xenografted tissue in an era before immunosuppression had no realistic prospect of surviving and functioning.
Was Steinach a fraud? His theory was wrong, not dishonest — a reasoned inference about how a gland might compensate, published and taken seriously by his peers.[1] The failure was that it was adopted at scale before it was tested.
Why did people believe it worked? Because the outcomes were subjective and the expectation was enormous. This is the same mechanism that made Brown-Séquard's essentially inert extract convincing to Brown-Séquard.[3]
Is anything from this era still in use? No. Rejuvenation surgery faded from 1935 with the arrival of synthetic androgens.[1] Modern therapy replaces the hormone directly at measured doses, against a defined target.[4]
Next in this series
Seventeen years of surgery ended because three laboratories, working separately, finally caught the molecule itself.
Continue with the year they got the molecule right.
References
4 sources
- Schultheiss D, Denil J, Jonas U. Rejuvenation in the early 20th century. Andrologia. 1997;29(6):351–355. doi:10.1111/j.1439-0272.1997.tb00329.x · PMID 9430441
- Nieschlag E, Nieschlag S. ENDOCRINE HISTORY: The history of discovery, synthesis and development of testosterone for clinical use. Eur J Endocrinol. 2019;180(6):R201–R212. doi:10.1530/EJE-19-0071 · PMID 30959485
- Cussons AJ, Bhagat CI, Fletcher SJ, et al. Brown-Séquard revisited: a lesson from history on the placebo effect of androgen treatment. Med J Aust. 2002;177(11-12):678–679. doi:10.5694/j.1326-5377.2002.tb05014.x · PMID 12463999
- Bhasin S, Brito JP, Cunningham GR, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715–1744. doi:10.1210/jc.2018-00229 · PMID 29562364
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