Calculation Of Circulating Levodopa From The Mesenteric System, The Brain

Based on the paper “Substantial Production of Dopamine in the Human Gastrointestinal Tract “, 1997 by Eisenhofer et al , I wanted to see if I could develop a reasonable estimate for the amount of levodopa produced by the mesenteric system, and the amount of levodopa produced by the brain. The thinking is that we could put into perspective the contributions of your medicine, your gut, and your brain if your battling PD. So I used the information in the paper to perform calculations as follows:

How much Levodopa does the mesenteric system produce?

Levodopa molecular weight = 197.19g/MOL= 197.19 ng/nmol

Table 2,
States net mesenteric DOPA production as:
.65 nmol/min

197.19ng/nmol * .65 nmol/min = 128.17 ng/min,  * 1mg/1E6ng = .128E-3 mg/min

Mesenteric Daily Production:
.128mg/min * 60min/hr *24hrs/day = 184.32 mg/day
Comparable to 2 Sinamet 100/25 per day.

Please note that this is conservative because all the individuals studied in the paper had either gut cancer, pancreatic illness, or heart disease.

The article states: “Up to 46% of the DA formed in the body ... is derived from the gastrointestinal tract, pancreas, and spleen.” Given that some of the remainder is produced in the peripheral nervous system, perhaps a generous estimate is that 50% is produced by the brain. So we have about another 2 Sinamet being produced in a healthy brain. Estimates widely cited have indicated that brain production is 50% compromised in the PD affected by brain at onset. So the brain is producing about 1 Sinemet at onset of symptoms for PWP.

In summary :

Mesenteric System (gut, pancreas, spleen) - produces about 2 Sinamet per day

Parkinson’s brain at onset - 1 Sinamet per day

So this seems to imply that if you’re taking more that 1 Sinamet per day as a PWP, you’re fighting another Dragon besides brain disease (something in your periphery is either failing to produce levodopa, overactively converting levodopa to dopamine, and/or overactively destroying levodopa)  Possibilities include an overactive liver, overactive kidneys, and/or an unhealthy gut, unhealthy pancreas, improper vitamin B6 balance (and B6 is involved in 100
different processes), insufficient production of AADC enzyme and/or an unhealthy spleen.

Notice how very little levodopa is normally produced by your body. Depending on your stage of Parkinson’s and how much levodopa you’re taking, your medication dose can be 50x, 500x, or 5000x what the body normally produces. So it’s no wonder, results vary widely and side effects abound.

Find the article at:

https://academic.oup.com/jcem/article/82/11/3864/2866142