But if the body really wanted to get rid of those nutrients and hormones, if would be logical to expect, after re-introduction, the next urine to be double concentrated. Instead it is exactly the contrary, the urine being much clearer.
But the body is eliminating those things for a reason. For example the body may have an excess of estrogen so it eliminates it through the urine. If the body already has an excess of estrogen why would you ingest the excess the body was eliminating? Same goes for glucose. Diabetics dump a lot of the excess glucose through the urine. So if the blood sugar is already high then why would someone ingest more glucose from the urine?
We can generally get what we need through diet, and by keeping our digestive and endocrine systems in proper working order.
The same can be said for sweat, and I can't see anyone wanting to drink their own sweat either, unless they were in dire need of salts.
Gladiator sweat used to bring a lot of money being sold as an aphrodisiac. We secrete a lot of pheromones in our sweat, but tend to cover them up with deodorants, perfumes, colognes, scented soaps, etc. No wonder we are so confused about relationships
Urine does not just contain urea and ammonia.
http://www.nlm.nih.gov/medlineplus/ency/article/003605.htm
"A test can be done to measure the amount of urea in the urine."
http://en.wikipedia.org/wiki/Urine
"To eliminate soluble wastes, which are toxic, most animals have excretory systems. In humans soluble wastes are excreted by way of theurinary system, which consists of the kidneys, ureters, urinary bladder, and urethra. The kidneys extract the soluble wastes from the bloodstream, as well as excess water, sugars, and a variety of other compounds. The composition of urine is adjusted in the process of reabsorption whereby certain solutes, such as glucose, are reabsorbed back into the blood stream via carrier molecules.[citation needed] The remaining fluid contains high concentrations of urea and other substances, including toxins."
From a urine therapy site:
http://www.vanderbilt.edu/AnS/psychology/health_psychology/Urine_Therapy.htm
"Urine, 95% of which is water, 2.5% of which is urea"
"The following are the average quantities of various substances, in 100 milliliters of urine as reported in Introduction to Biochemistry by Dr. Pharon:
Substance Milligrams
1] Urea nitrogen
682.00
2] Urea
1459.00
3] Creatinin nitrogen
36.00
4] Creatinin
97.20
5] Uric acid nitrogen
12.30
6] Uric acid
36.90
7] Amino nitrogen
9.70
8] Ammonia nitrogen
57.00"
If you want to argue that urine contains the ammonium ion rather than ammonia you still ahve to keep in mind that oxidation will convert the ammonium ion will oxidize back in to ammonia. So as soon as it hits air this process starts. If you drink water with the urine then that will proved additional oxygen for ammonia formation. Then there is the metabolic processing of the ammonium, which will likely involve oxygen converting the ammonium in to ammonia.
Some information on the effects of urea ingestion. Read down a ways and they do cover human subjects:
http://www.inchem.org/documents/jecfa/jecmono/v32je16.htm