Richard Kay
@richard-kay.bsky.social
Passionate about using mass spectrometry for studying disease. Clinical mass spectrometry (bioactive peptides and proteins) in the day, average triathlete in my spare time!
Didn't see much active GLP-I in our LC-MS analyses. Vast majority is 1-36 or 1-37.
September 28, 2025 at 11:04 AM
Didn't see much active GLP-I in our LC-MS analyses. Vast majority is 1-36 or 1-37.
We have a potential MRC iCASE PhD with AstraZeneca using mass spectrometric techniques to identify the destination organs of endogenous and exogenous peptide hormones. This should be a really interesting PhD, using both ours and AstraZeneca's expertise and mass spectrometry instrumentation.
September 26, 2025 at 11:38 AM
We have a potential MRC iCASE PhD with AstraZeneca using mass spectrometric techniques to identify the destination organs of endogenous and exogenous peptide hormones. This should be a really interesting PhD, using both ours and AstraZeneca's expertise and mass spectrometry instrumentation.
*Orbitrap... Stupid autocorrect...
August 15, 2025 at 4:30 PM
*Orbitrap... Stupid autocorrect...
Have done that and we get a match for the de-glycosylated peptide (strong signal too) I just can't find the glycosylated one. Have even drawn up some theoretical structures of the peptide to try identify peaks..
August 13, 2025 at 10:18 AM
Have done that and we get a match for the de-glycosylated peptide (strong signal too) I just can't find the glycosylated one. Have even drawn up some theoretical structures of the peptide to try identify peaks..
Yes. Pretty short. I can just about make out y1, 2 and 3..
August 13, 2025 at 9:30 AM
Yes. Pretty short. I can just about make out y1, 2 and 3..
Interestingly - metformin is being investigated as a prophylactic for nausea and vomiting in pregnancy. It does this by raising GDF15 prior to its meteoric plasma spike during the gestational period.
August 5, 2025 at 12:04 PM
Interestingly - metformin is being investigated as a prophylactic for nausea and vomiting in pregnancy. It does this by raising GDF15 prior to its meteoric plasma spike during the gestational period.
Mounjaro is a clever peptide, a mixture of three.. GIP, GLP-1 and a peptide from lizard venom!
August 5, 2025 at 11:37 AM
Mounjaro is a clever peptide, a mixture of three.. GIP, GLP-1 and a peptide from lizard venom!
This becomes worse when they come off and put weight on again - having lost muscle mass in the weight loss process.
The BMJ released an article about this recently.
Weight loss treatment should come with exercise as well to stave off muscle loss..
The BMJ released an article about this recently.
Weight loss treatment should come with exercise as well to stave off muscle loss..
August 5, 2025 at 7:11 AM
This becomes worse when they come off and put weight on again - having lost muscle mass in the weight loss process.
The BMJ released an article about this recently.
Weight loss treatment should come with exercise as well to stave off muscle loss..
The BMJ released an article about this recently.
Weight loss treatment should come with exercise as well to stave off muscle loss..
They are amazing - they way they have extended half lives of endogenous peptides from 3 mins to 3.5 days is phenomenal.
The issue could be that they are worried about side effects. One issue is lean muscle mass loss (as well as fat). If this is lost, then it can also be harmful.
The issue could be that they are worried about side effects. One issue is lean muscle mass loss (as well as fat). If this is lost, then it can also be harmful.
August 5, 2025 at 7:11 AM
They are amazing - they way they have extended half lives of endogenous peptides from 3 mins to 3.5 days is phenomenal.
The issue could be that they are worried about side effects. One issue is lean muscle mass loss (as well as fat). If this is lost, then it can also be harmful.
The issue could be that they are worried about side effects. One issue is lean muscle mass loss (as well as fat). If this is lost, then it can also be harmful.
I am a regular volunteer for our studies, but we are unlikely to get ethics to dose healthy subject with them.
The switching off of "food noise" in some people is very effective, but in those who don't have this it could be dangerous.
Apparently, when you stop taking them, the voices return.
The switching off of "food noise" in some people is very effective, but in those who don't have this it could be dangerous.
Apparently, when you stop taking them, the voices return.
August 5, 2025 at 6:54 AM
I am a regular volunteer for our studies, but we are unlikely to get ethics to dose healthy subject with them.
The switching off of "food noise" in some people is very effective, but in those who don't have this it could be dangerous.
Apparently, when you stop taking them, the voices return.
The switching off of "food noise" in some people is very effective, but in those who don't have this it could be dangerous.
Apparently, when you stop taking them, the voices return.
Our group are doing research with both these peptides and how they change other gut hormones. We are performing clinical studies in specific disease states, however getting similar data from healthy individuals in our clinic is an issue, as with these peptides blunt appetite so much!
August 5, 2025 at 6:54 AM
Our group are doing research with both these peptides and how they change other gut hormones. We are performing clinical studies in specific disease states, however getting similar data from healthy individuals in our clinic is an issue, as with these peptides blunt appetite so much!
The lab next door to me use an MSD multiplex kit that can get to sub pg/mL.
Not a mass spec based approach, but it also measures lots of other interleukins as well.
Not a mass spec based approach, but it also measures lots of other interleukins as well.
August 4, 2025 at 9:29 AM
The lab next door to me use an MSD multiplex kit that can get to sub pg/mL.
Not a mass spec based approach, but it also measures lots of other interleukins as well.
Not a mass spec based approach, but it also measures lots of other interleukins as well.
The 1031.58 ion is a dimer of 516, which shows up if it is selected for MS/MS.
July 31, 2025 at 8:53 AM
The 1031.58 ion is a dimer of 516, which shows up if it is selected for MS/MS.
That potentially could be an in-source dimer. They only have 1+, but are double the m/z (well, double the m/z -1)
July 31, 2025 at 8:40 AM
That potentially could be an in-source dimer. They only have 1+, but are double the m/z (well, double the m/z -1)
Probably highly unlikely, but we get contaminants in our extracts (problematic bile salts..) that sometimes form in-source dimers. We see a singly charged ion of ~1031m/z, which is actually a dimer of a compound of 516 m/z. Probably highly unlikely...
July 31, 2025 at 8:20 AM
Probably highly unlikely, but we get contaminants in our extracts (problematic bile salts..) that sometimes form in-source dimers. We see a singly charged ion of ~1031m/z, which is actually a dimer of a compound of 516 m/z. Probably highly unlikely...
In these specific disease states, the plasma level finally crept above the LC-MS/MS (and immunoassay) detection limit for a little while - as with most peptides it has a maddenignly short half life.
A very hard peptide to find and analyse... a big tick against that one!!
A very hard peptide to find and analyse... a big tick against that one!!
July 29, 2025 at 9:08 AM
In these specific disease states, the plasma level finally crept above the LC-MS/MS (and immunoassay) detection limit for a little while - as with most peptides it has a maddenignly short half life.
A very hard peptide to find and analyse... a big tick against that one!!
A very hard peptide to find and analyse... a big tick against that one!!
Insulin Like Peptides 5 (INSL5) circulates at very low levels, it is hydrophobic, causes horrible carryover, has poor fragmentation in MS/MS, and to top it off it is only produced in the distal colon from cells that total 0.1-1% of all gut epithelial cells.
One of those peptides....
One of those peptides....
July 29, 2025 at 9:08 AM
Insulin Like Peptides 5 (INSL5) circulates at very low levels, it is hydrophobic, causes horrible carryover, has poor fragmentation in MS/MS, and to top it off it is only produced in the distal colon from cells that total 0.1-1% of all gut epithelial cells.
One of those peptides....
One of those peptides....