Glycine stimulates growth hormone release in man
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I found this article to be interesting. Just for the record, I do not think that it is good to mainline glycine.
Glycine stimulates growth hormone release in man (1980)
Abstract
The influence of glycine, the simplest amino acid, on pituitary function has been investigated in the present study.
Different doses (4, 8 or 12 g) of glycine were intravenously infused over 15 or 30 min in normal subjects. Serum levels of GH (growth hormone) and Prl (prolactin) were measured before and after the infusion, and also blood sugar levels were determined.
The dose of 4 or 8 g glycine induced a significant increase in serum GH (P < 0.05 or P< 0.001, respectively); however, a more pronounced and significant increase in serum GH levels was observed after infusion at a dose of 12 g glycine (P < 0.001). It was clearly observed that the dose-dependent GH release to intravenous glycine occurred in normal subjects. On the contrary, serum Prl level was not changed significantly, and blood sugar level was transiently, but significantly (P < 0.05), increased after the infusion of 12 g glycine.
The present data suggest that glycine might play an important role in the control of hypothalamic-pituitary function.
"Without a realistic view of where you are, you can't expect to go anywhere." Ray Peat (1936-2022) 👀
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@DavidPS said in Glycine stimulates growth hormone release in man:
Different doses (4, 8 or 12 g) of glycine were intravenously infused
When taking 10 g glycine (through stomach digestion), only 2 g is assimilated. Dixit Haidut on RPF.
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@LucH - thanks for the information. I limit my glycine to dietary sources. But I thought this was interesting.
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@LucH Does this suggest that glycine has a 20% digestion rate, or that only 2 grams can be digested at a time?
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@William-Shat
None of both ones. Transport is limited because of capacity and efficacity of "carryers". -
Too much glycine?
What happens if you use too much glycine (supplement)?
=> You need more B9 as 5-MTHF.
First there is no danger of over-consumption except mild action on energy (GABA pathway, slow-down signal to the brain, aka depression by some users) but we burden the methyl pathway by over-using folate. So you need co-enzyme B9 as 5-MTHF (not simply folic acid).
The breakdown of glycine by the glycine cleavage system produces a molecule called a methyl group. This molecule is added to and used by a vitamin called folate. Folate is required for many functions in the cell and is important for brain development.
How much glycine?
In an article posted by Haidut, he said 2 g from 10 g glycine were absorbed. 20% assimilation rate.
Why? The problem is due the capacity of peptide carriers through the brush border and the capacity of hydrolase enzymes in intestines.Collagen protein supplements Vs glycine powder
This is likely more efficient, as glycine competes with other amino acids for absorption and is therefore absorbed less efficiently by itself than when it's bound to other amino acids, as in the case of collagen (43,44).
43. Absorption of glycine and L-alanine by the human jejunum.
doi: 10.1172/JCI105451 J Clin Invest. 1966.
=> The assimilation is dependent on the active transport and affinity (competition for intestinal transport).
Note: No need to read further.
44. Functional characterization of dipeptide transport system in human jejunum
DOI: 10.1172/JCI107685 J Clin Invest 1974.
=> No useful info on single peptide.Note 1: I didn’t find back the original post (posted on RPF), nor on Haidut’s site.
Note 2: When taking collagen powder, 10 g of powder is advised per day. Better absorption rate when taken apart from a meal. -
I try to remain within the ranges that Dr. Peat mentions in Gelatin, stress, longevity (2009)
Gelatin (the cooked form of collagen) makes up about 50% of the protein in an animal, but a much smaller percentage in the more active tissues, such as brain, muscle, and liver. 35% of the amino acids in gelatin are glycine, 11% alanine, and 21% proline and hydroxyproline.
The 1936 Cyclopedia of Medicine (G.M. Piersol, editor, volume 6) mentions the use of gelatin solution to quickly control nosebleeds, excessive menstrual bleeding, bleeding ulcers (using three doses of 18 grams as a 10% solution during one day), and bleeding from hemorrhoids and the lower bowel, and hemorrhage from the bladder. But since Selye's work relating the thrombohemorrhagic syndromes to stress wasn't known at that time, gelatin was thought of as a useful drug, rather than as having potentially far-reaching physiological effects, antagonizing some of the agents of stress-induced tissue damage.
Although I pointed out a long time ago the antithyroid effects of excessive cysteine and tryptophan from eating only the muscle meats, and have been recommending gelatinous broth at bedtime to stop nocturnal stress, it took me many years to begin to experiment with large amounts of gelatin in my diet. Focusing on the various toxic effects of tryptophan and cysteine, I decided that using commercial gelatin, instead of broth, would be helpful for the experiment. For years I hadn't slept through a whole night without waking, and I was in the habit of having some juice or a little thyroid to help me go back to sleep. The first time I had several grams of gelatin just before bedtime, I slept without interruption for about 9 hours. I mentioned this effect to some friends, and later they told me that friends and relatives of theirs had recovered from long-standing pain problems (arthritic and rheumatic and possibly neurological) in just a few days after taking 10 or 15 grams of gelatin each day.
In some of the older studies, therapeutic results improved when the daily gelatin was increased. Since 30 grams of glycine was commonly used for treating muscular dystrophy and myasthenia gravis, a daily intake of 100 grams of gelatin wouldn't seem unreasonable, and some people find that quantities in that range help to decrease fatigue. For a growing child, though, such a large amount of refined gelatin would tend to displace other important foods. The National Academy of Sciences recently reviewed the requirements for working adults (male and female soldiers, in particular), and suggested that 100 grams of balanced protein was needed for efficient work. For adults, a large part of that could be in the form of gelatin.
If a person eats a large serving of meat, it's probably helpful to have 5 or 10 grams of gelatin at approximately the same time, so that the amino acids enter the blood stream in balance.
