Study analysis · The Journal of biological chemistry · 1979
These two hormones turn your liver into a sugar factory—without using the signal everyone thought was essential.
Two hormones, angiotensin II and vasopressin, make your liver release more sugar by flipping a calcium switch, not the usual cAMP switch that glucagon uses.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
In simple terms
This study looked at how certain hormones affect tiny parts inside liver cells in a test tube. It shows a possible way they might work, but it doesn't prove this happens in people or causes any real health effects.
What’s the bottom line?
Two hormones, angiotensin II and vasopressin, tell the liver to make more sugar by changing how certain enzymes are tagged, without using the usual sugar-making signal. Glucagon does the same thing but uses a different signal.
How strong is this study?
The scientists did a careful job inside the lab with the cells they had, but we don't know how they picked the cells or if anything else messed up the results. That means we can't fully trust that this is how things work in real life.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
19 / 100
- Randomizationrandomization unclear
- Blindingblinding unclear
- Control group+15/15
- Sample sizeno sample size reported
- Follow-upno follow-up reported
100 / 100
31 / 100
- P-valuesno p-values reported
- Effect size+20/20
- Confidence intervalsno confidence intervals
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 534 / 100
Probability of being correct
Researchers compare people who have a condition (cases) with similar people who do not (controls), looking back in time for differences in exposure. Useful but more prone to bias.
This design cannot establish causation — the findings describe an association, not a cause. Study is in vitro and lacks randomization, control group details, and human participants; cannot establish causation without explicit experimental design evidence.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding information were disclosed in the provided text.
The study describes mechanistic biochemical findings without any disclosure of funding, author affiliations, or conflicts of interest. No industry ties or funder involvement can be inferred from the provided text.
Key takeaways
- 01
Angiotensin II and vasopressin increased phosphorylase activity by 250–260%, decreased glycogen synthase activity by 50%, and decreased pyruvate kinase activity by 30–70%.
- 02
These changes only happened when calcium was present.
- 03
Yes — these changes mean the liver produces more glucose and stores less, which could raise blood sugar levels — important for understanding how stress or dehydration might trigger high blood sugar.
Surprising findings
- Angiotensin II and vasopressin trigger the exact same enzyme changes as glucagon—but without using cAMP.For decades, glucagon’s cAMP pathway was considered the primary route for liver glucose release. Finding that two other hormones bypass it entirely and use calcium instead contradicts textbook models.
Practical takeaways
If you're prone to high blood sugar during stress or dehydration, staying hydrated and managing stress may help reduce unintended glucose spikes.
This study was done on isolated liver cells in a lab—no human trials were conducted. The real-world impact is still theoretical.
low confidenceWhy this study matters
Calcium vs. cAMP: The Hidden Sugar Switch
Angiotensin II and vasopressin increase phosphorylation of 10–12 liver proteins—including phosphorylase, glycogen synthase, and pyruvate kinase—without changing cAMP levels. Glucagon does the same thing, but only by boosting cAMP. When calcium is removed, angiotensin II and vasopressin lose all effect, but glucagon still works.
This reveals a completely different biological pathway for controlling blood sugar—one that doesn’t rely on the well-known cAMP signal. It suggests stress or dehydration (which trigger these hormones) might spike blood sugar in ways we didn’t fully understand.
260% Sugar Boost—No cAMP Needed
Angiotensin II and vasopressin increased phosphorylase activity by 250–260%, decreased glycogen synthase by 50%, and reduced pyruvate kinase by 30–70%. These changes directly link to increased glucose production and reduced storage. All of this happened without any measurable change in cAMP.
It’s shocking that such a massive metabolic shift can happen without the body’s most famous sugar-regulating signal. This could explain why some people with normal insulin levels still get high blood sugar under stress.
The Calcium Lock: Why Removing It Erases the Effect
When hepatocytes were placed in calcium-free medium, angiotensin II and vasopressin lost all ability to trigger enzyme phosphorylation or activity changes. Glucagon’s effects remained unchanged. This proves calcium is essential for this pathway.
It’s rare to see such a clean on/off switch in biology. This could lead to new ways to block stress-induced blood sugar spikes without touching insulin or cAMP.
Want the whole report?
Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Two hormones, angiotensin II and vasopressin, tell the liver to make more sugar by changing how certain enzymes are tagged, without using the usual sugar-making signal. Glucagon does the same thing but uses a different signal.
Research results
Angiotensin II and vasopressin increased phosphorylase activity by 250–260%, decreased glycogen synthase activity by 50%, and decreased pyruvate kinase activity by 30–70%. These changes only happened when calcium was present.
What this means - more context
Yes — these changes mean the liver produces more glucose and stores less, which could raise blood sugar levels — important for understanding how stress or dehydration might trigger high blood sugar.
The study investigates whether angiotensin II and vasopressin regulate hepatic carbohydrate metabolism via a calcium-dependent, cyclic AMP-independent pathway that alters enzyme phosphorylation.
Angiotensin II and vasopressin increase phosphorylation of 10–12 cytosolic proteins in isolated hepatocytes without changing cyclic AMP levels, while glucagon does so via cyclic AMP. Phosphorylation of phosphorylase, glycogen synthase, and pyruvate kinase correlates with increased phosphorylase activity (250–260%), decreased glycogen synthase activity (50%), and decreased pyruvate kinase activity (30–70%). These effects are abolished in Ca2+-free medium for angiotensin II and vasopressin but not for glucagon.
Methods Used
Isolated hepatocytes labeled with [32P]PO43- were treated with angiotensin II, vasopressin, or glucagon. Cytosolic proteins were separated via SDS-polyacrylamide gel electrophoresis. Phosphorylation was assessed by radiolabeling; enzyme activities were measured. Affinity chromatography and immunoprecipitation identified specific phosphoproteins. Experiments were repeated in Ca2+-free medium to test calcium dependence.
Main Finding
Angiotensin II and vasopressin increase phosphorylation of 10–12 cytosolic proteins (including phosphorylase, glycogen synthase, and pyruvate kinase) via a Ca2+-dependent, cyclic AMP-independent pathway, leading to a 250–260% increase in phosphorylase activity, 50% decrease in glycogen synthase activity, and 30–70% decrease in pyruvate kinase activity. Glucagon produces identical phosphorylation changes via cyclic AMP.
Confidence Level
Limited - based on abstract only, full methodology not available
Study Flags
Red Flags
- •Full text not available - methodology details cannot be verified
- •No human or in vivo data — results based on isolated hepatocytes only
- •Effect sizes reported but no statistical significance or p-values provided
Surprising Findings
Angiotensin II and vasopressin trigger the exact same enzyme changes as glucagon—but without using cAMP.
For decades, glucagon’s cAMP pathway was considered the primary route for liver glucose release. Finding that two other hormones bypass it entirely and use calcium instead contradicts textbook models.
Practical Takeaways
If you're prone to high blood sugar during stress or dehydration, staying hydrated and managing stress may help reduce unintended glucose spikes.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 534 / 100
Probability of being correct
Researchers compare people who have a condition (cases) with similar people who do not (controls), looking back in time for differences in exposure. Useful but more prone to bias.
Case-Control Study
Subject
Lower probability
on the GRADE evidence scale
This study looked at how certain hormones affect tiny parts inside liver cells in a test tube. It shows a possible way they might work, but it doesn't prove this happens in people or causes any real health effects.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Clear biochemical measurements using radiolabeling and electrophoresis
- Use of Ca2+-free medium as a controlled condition to test mechanism
- Identification of specific enzymes via affinity chromatography and immunoprecipitation
Weaknesses
- Full methodology not available - based on abstract only
- No randomization or control group details provided
- No in vivo or human data
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Two hormones, angiotensin II and vasopressin, tell the liver to make more sugar by changing how certain enzymes are tagged, without using the usual sugar-making signal. Glucagon does the same thing but uses a different signal.
Research results
Angiotensin II and vasopressin increased phosphorylase activity by 250–260%, decreased glycogen synthase activity by 50%, and decreased pyruvate kinase activity by 30–70%. These changes only happened when calcium was present.
What this means - more context
Yes — these changes mean the liver produces more glucose and stores less, which could raise blood sugar levels — important for understanding how stress or dehydration might trigger high blood sugar.
The study investigates whether angiotensin II and vasopressin regulate hepatic carbohydrate metabolism via a calcium-dependent, cyclic AMP-independent pathway that alters enzyme phosphorylation.
Angiotensin II and vasopressin increase phosphorylation of 10–12 cytosolic proteins in isolated hepatocytes without changing cyclic AMP levels, while glucagon does so via cyclic AMP. Phosphorylation of phosphorylase, glycogen synthase, and pyruvate kinase correlates with increased phosphorylase activity (250–260%), decreased glycogen synthase activity (50%), and decreased pyruvate kinase activity (30–70%). These effects are abolished in Ca2+-free medium for angiotensin II and vasopressin but not for glucagon.
Methods Used
Isolated hepatocytes labeled with [32P]PO43- were treated with angiotensin II, vasopressin, or glucagon. Cytosolic proteins were separated via SDS-polyacrylamide gel electrophoresis. Phosphorylation was assessed by radiolabeling; enzyme activities were measured. Affinity chromatography and immunoprecipitation identified specific phosphoproteins. Experiments were repeated in Ca2+-free medium to test calcium dependence.
Main Finding
Angiotensin II and vasopressin increase phosphorylation of 10–12 cytosolic proteins (including phosphorylase, glycogen synthase, and pyruvate kinase) via a Ca2+-dependent, cyclic AMP-independent pathway, leading to a 250–260% increase in phosphorylase activity, 50% decrease in glycogen synthase activity, and 30–70% decrease in pyruvate kinase activity. Glucagon produces identical phosphorylation changes via cyclic AMP.
Confidence Level
Limited - based on abstract only, full methodology not available
Study Flags
Red Flags
- •Full text not available - methodology details cannot be verified
- •No human or in vivo data — results based on isolated hepatocytes only
- •Effect sizes reported but no statistical significance or p-values provided
Surprising Findings
Angiotensin II and vasopressin trigger the exact same enzyme changes as glucagon—but without using cAMP.
For decades, glucagon’s cAMP pathway was considered the primary route for liver glucose release. Finding that two other hormones bypass it entirely and use calcium instead contradicts textbook models.
Practical Takeaways
If you're prone to high blood sugar during stress or dehydration, staying hydrated and managing stress may help reduce unintended glucose spikes.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 534 / 100
Probability of being correct
Researchers compare people who have a condition (cases) with similar people who do not (controls), looking back in time for differences in exposure. Useful but more prone to bias.
Case-Control Study
Subject
Lower probability
on the GRADE evidence scale
This study looked at how certain hormones affect tiny parts inside liver cells in a test tube. It shows a possible way they might work, but it doesn't prove this happens in people or causes any real health effects.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Clear biochemical measurements using radiolabeling and electrophoresis
- Use of Ca2+-free medium as a controlled condition to test mechanism
- Identification of specific enzymes via affinity chromatography and immunoprecipitation
Weaknesses
- Full methodology not available - based on abstract only
- No randomization or control group details provided
- No in vivo or human data
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
The scientists did a careful job inside the lab with the cells they had, but we don't know how they picked the cells or if anything else messed up the results. That means we can't fully trust that this is how things work in real life.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
19 / 100
- Randomizationrandomization unclear
- Blindingblinding unclear
- Control group+15/15
- Sample sizeno sample size reported
- Follow-upno follow-up reported
100 / 100
31 / 100
- P-valuesno p-values reported
- Effect size+20/20
- Confidence intervalsno confidence intervals
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 534 / 100
Probability of being correct
Researchers compare people who have a condition (cases) with similar people who do not (controls), looking back in time for differences in exposure. Useful but more prone to bias.
This design cannot establish causation — the findings describe an association, not a cause. Study is in vitro and lacks randomization, control group details, and human participants; cannot establish causation without explicit experimental design evidence.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding information were disclosed in the provided text.
The study describes mechanistic biochemical findings without any disclosure of funding, author affiliations, or conflicts of interest. No industry ties or funder involvement can be inferred from the provided text.
Standing
Who’s using this study?
The videos and claims on this site that lean on this study, and the researchers who wrote it.
1 video from Thomas DeLauer cite this study, drawing 1 claim from it.
- Very strong evidence
Randomized or controlled trials support this claim, alongside consistent supporting evidence.
Evidence
Authored by
4 researchersIf this is your work, this is how we attribute it on Fit Body Science. James C. Garrison is listed as the lead author.