RalphADeFronzoMD

Endocrinology • San Antonio, TX

Diabetes

Endocrinologist, University Texas Health Science Center

Join to view full profile

Dr. DeFronzo is on Doximity

As a Doximity member you'll join over two million verified healthcare professionals in a private, secure network.

Gain access to free telehealth tools, such as our “call shielding” and one-way patient texting.
Connect with colleagues in the same hospital or clinic.
Read the latest clinical news, personalized to your specialty.

See Dr. DeFronzo's full profile

Already have an account?

Office
701 S Zarzamora
San Antonio, TX 78207
Phone+1 210-358-7500

Fax+1 210-358-7515

Summary

Dr. Ralph DeFronzo is an endocrinologist in San Antonio, TX and is affiliated with multiple hospitals in the area, including University Health / UT Health Science Center at San Antonio, South Texas Veterans Health Care System, and University Health / UT Health Science Center at San Antonio. He received his medical degree from Harvard Medical School and has been in practice 48 years. He specializes in diabetes and is experienced in diabetes. He has more than 800 publications and over 500 citings.

Education & Training

University of Pennsylvania Health SystemResidency, Internal Medicine, 1973 - 1975
Johns Hopkins UniversityResidency, Internal Medicine, 1969 - 1971
Harvard Medical SchoolClass of 1969
Icahn School of Medicine at Mount Sinai/NYC Health and Hospitals (Elmhurst)Fellowship, Child and Adolescent Psychiatry

Certifications & Licensure

TX State Medical License 1990 - 2025
MD State Medical License 1970 - 1982
American Board of Internal Medicine Internal Medicine
American Board of Internal Medicine Nephrology

Clinical Trials

Actos Now for Prevention of Diabetes (ACT NOW) Start of enrollment: 2004 Jan 01
Completed
Phase 3
Acute Metabolic Effects of LAF 237 in Type 2 Diabetics Start of enrollment: 2004 Nov 01
Completed
Phase 3
Durability of Combination Therapy With Exenatide/Pioglitazone/Metformin vs. Conventional Therapy in New Onset T2DM Start of enrollment: 2009 Jan 01
Completed
Phase 4
Study of Dapagliflozin on Mitochondrial Dysfunction and Impaired Insulin Signaling/Action Start of enrollment: 2011 Mar 01
Completed
Not Applicable
Myocardial Dysfunction in Type 2 Diabetes Mellitus (T2DM) Start of enrollment: 2006 Jun 01
Completed
Phase 4
A Comparative Effectiveness Study of Major Glycemia-lowering Medications for Treatment of Type 2 Diabetes Start of enrollment: 2013 May 01
Completed
Phase 3
Safety, Tolerability, Pharmacokinetic (PK) and Pharmacodynamic (PD) Study of G-Pen(TM) (Glucagon Injection) to Treat Severe Hypoglycemia Start of enrollment: 2013 Oct 01
Completed
Phase 2
A Euglycemic Insulin Clamp Study in Type 1 Diabetic Patients With Oral Insulin (ORAMED) Start of enrollment: 2015 Jan 01
Completed
Phase 2
SGLT2 Inhibition and Stimulation of Endogenous Glucose Production: Protocol 2 Start of enrollment: 2015 Oct 23
Completed
Phase 3
ESR-15-11293 - Saxa/Dapa, Safety and Efficacy Study Start of enrollment: 2016 Jan 01
Completed
Not Applicable
Pre-diabetes in Subject With Impaired Fasting Glucose (IFG) and Impaired Glucose Tolerance (IGT) Start of enrollment: 2014 Jan 01
Recruiting
Not Applicable
PROTOCOL 3: Role of the Renal Nerves in the Increase in EGP in Response to Glucosuria Start of enrollment: 2016 Oct 01
Completed
Phase 4
Can Exenatide Prevent Increase in EGP in Response to Dapagliflozin-induced Increase in Glucosuria Start of enrollment: 2018 Feb 28
Completed
Phase 4
Ketones, Muscle Metabolism, and SGLT2 Inhibitors - Protocol 1 Start of enrollment: 2019 Jan 07
Recruiting
Phase 1
Evaluation of Intra-Abdominal Fat Extraction Using HydraSolve T2D™ in Obese Subjects With Type 2 Diabetes Start of enrollment: 2019 Oct 18
Recruiting
Not Applicable
Effect of Physiologic Hyperglucogonemia on Adipocyte Metabolism Start of enrollment: 2018 Feb 05
Active, not recruiting
Early Phase 1
Roles: Principal Investigator, Contact
Effect of Ketogenic Diet on Glucose Metabolism and Energy Expenditure in Type 2 Diabetes Start of enrollment: 2020 Nov 25
Completed
Not Applicable
Roles: Contact, Principal Investigator
Effect of Chronic Exenatide Therapy on Beta Cell Function and Insulin Sensitivity in T2DM Start of enrollment: 2017 Dec 15
Completed
Phase 4
Roles: Contact
Effect of Dapagliflozin on Hepatic and Renal Glucose Metabolism Subjects Start of enrollment: 2019 May 23
Completed
Phase 4
Roles: Contact
Effect of Novel Glucagon Receptor Antagonist REMD-477 on Glucose and Adipocyte Metabolism in T2DM Start of enrollment: 2021 Nov 10
Suspended
Early Phase 1
Roles: Principal Investigator, Contact
Pioglitazone on Heart Failure in Type-2 Diabetes Mellitus Participants Start of enrollment: 2023 Jul 10
Recruiting
Phase 4
Roles: Contact, Principal Investigator
SGLT2 Inhibitors, Ketogenesis, and Ketoacidosis Start of enrollment: 2023 Oct 05
Recruiting
Early Phase 1
Roles: Contact, Principal Investigator
Ketones, SGLT2, HFrEF Start of enrollment: 2024 Jan 25
Recruiting
Early Phase 1
Roles: Contact, Principal Investigator
Join now to see all

Publications & Presentations

PubMed

4434 citations
Insulin sensitivity indices obtained from oral glucose tolerance testing: comparison with the euglycemic insulin clamp.
Masafumi Matsuda, Ralph A. DeFronzo
Diabetes Care. 1999-09-01
1259 citations
Skeletal Muscle Insulin Resistance Is the Primary Defect in Type 2 Diabetes
Ralph A. DeFronzo, Devjit Tripathy
Diabetes Care. 2009-11-01
736 citations
Pathogenesis of type 2 diabetes mellitus
Ralph A. DeFronzo
The Medical Clinics of North America. 2004-07-01

Journal Articles

Mild Physiologic Hyperglycemia Induces Hepatic Insulin Resistance in Healthy Normal Glucose Tolerant Subjects
Rita Basu, Ralph A DeFronzo, Devjit Tripathy, The Journal of Clinical Endocrinology and Metabolism
Glucose-Mediated Glucose Disposal at Baseline Insulin Is Impaired in IFG
Ralph A DeFronzo, Rucha Mehta, Christina Agyin, John Adams, The Journal of Clinical Endocrinology and Metabolism

Lectures

Pioglitazone Prevents the Increase in Plasma Ketone Concentration Associated with Dapagliflozin in Insulin‐Treated T2DM Patients: Results from the Qatar Study
San Antonio, TX - 6/14/2014
Pioglitazone Prevents the Increase in Plasma Ketone Concentration Associated with Dapagliflozin in Insulin‐Treated T2DM Patients: Results from the Qatar Study
San Antonio, TX - 6/15/2014

Press Mentions

The Guidelines Specifically Recommend DPP-4 Inhibitors as Monotherapy for Patients with HbA1c Levels Between 6January 18th, 2023
DeFronzo Wins Global Prize for Work in Type 2 DiabetesNovember 29th, 2022
Two Diabetes Drug Classes Can Increase, Maintain Beta-Cell FunctionDecember 3rd, 2021
Join now to see all

Grant Support

Improved Hypoglycemia Rescue DeviceNational Institute Of Diabetes And Digestive And Kidney Diseases2011
Regulation Of Hepatic And Peripheral Glucose MetabolismNational Institute Of Diabetes And Digestive And Kidney Diseases1988–2010
Reactive Oxygen Species (Ros), Mitochondrial Dysfunction And T2D (Prot 1)National Center For Research Resources2008
Protocol V: Effect Of Chronically Elevated Plasma FFA On HGP And GluconeogenesisNational Center For Research Resources2008
Prot 1: Effect Of Physiologic Increase In FFA On Mitochondrial Func In NGT SubjNational Center For Research Resources2008
Mechanisms Of Action Of Exubera To Normalize Fasting Plasma Glucose In T2dmNational Center For Research Resources2008
Is Non-Diabetic Fasting Hyperglycemia Explained By Impaired Glucose UptakeNational Center For Research Resources2008
Clinical Trial: Effects Of 8 WKS Trtmt Of Vildagliptin,Exenatide, Or CombinationNational Center For Research Resources2008
Clinical Trial: A Double-Blind Study To Explore Effects Of Laf237 On Glucose DurNational Center For Research Resources2008
Effect Of Acute Elevation Of FFA On Mitochondrial Function In Skeletal MuscleNational Center For Research Resources2007–2008
Mechanism Of Insulin Sensitizing Effect Of Pioglitazone-Role Of AdiponectinNational Center For Research Resources2006–2008
Molecular Epidemiology Of Type 2 Diabetes Mellitus In Mexican AmericansNational Center For Research Resources2005–2008
Glycemic Control And Complications In Diabetes Mellitus Type 2National Center For Research Resources2005–2008
Protocol V: Effect Of Chronically Elevated Plasma FFA On HGP &GluconeogenesisNational Center For Research Resources2007
Effects Of 8 WKS Trtmt Of Vildagliptin,Exenaide, Or Combination In Patient W/T2dNational Center For Research Resources2007
Reactive Oxygen Species (Ros), Mitochondrial Dysfunction And Type 2 DiabetesNational Center For Research Resources2006–2007
Molecular EPI Of T2dm In MAS: Protocol 1: Expansion Of Vages FamiliesNational Center For Research Resources2006–2007
Role Of Serine Phos In Insulin Resistance In Vivo In Human Muscle (Nih Prot 2a)National Center For Research Resources2006
Actos NOW For Prevention Of Diabetes (Act Now)National Center For Research Resources2006
Prot V: Effect Of Chronically Elevated Plasma FFA On HGP And GluconeogenesisNational Center For Research Resources2005–2006
A Double-Blind Study To Explore Effects Of Laf237 On Glucose During OvernightNational Center For Research Resources2005–2006
Regulation Of Hepatic And Peripheral Glucose MetabolismNational Institute Of Diabetes And Digestive And Kidney Diseases2005
Effect Of Pioglitazone On Insulin Signaling And Muscle Fat ContentNational Center For Research Resources2005
Pioglitazone Splanchnic Gluc Uptake, Hepatic Gluc Prod, INS Senst, Mscl Fat ContNational Center For Research Resources2004–2005
Reduction Of Hyprinsulinemia--Glucose Metab/Insul SenseNational Center For Research Resources2004
Reduction In Plasma FFA Concentration With FenofilbrateNational Center For Research Resources2004
Pioglitazone--Insulin Signaling And Muscle Fat In PCOSNational Center For Research Resources2004
Nitric Oxide, Endothelial Dysfunction &Type 2 DiabetesNational Center For Research Resources2004
Molecular Epidemiology Of NIDDM In Mexican AmericansNational Center For Research Resources2004
Glycemic Control And Complications In NIDDMNational Center For Research Resources2004
Fenofibrate--Glucose/Lipid Metab In NIDDM &Insul SenseNational Center For Research Resources2004
Effect Of Acipimox On Glucose Metabolism In NIDDMNational Center For Research Resources2004
Chronically Elevated Plasma FFA On HGP &GluconeogenesisNational Center For Research Resources2004
Liver Action In Glucose Homeostasis In Diabetics/NormalsNational Center For Research Resources2000–2002
IGF1 On Muscle Glucose Phosphorylation And TransportNational Center For Research Resources2000–2002
IGF1 Effect On Lipid/Ffa Metabolism--Protocol VINational Center For Research Resources2000–2002
Hyperinsulinemia--Glucose Phosphorylation/TransportNational Center For Research Resources2000–2002
Glycolysis In Insulin Mediated Glucose DisposalNational Center For Research Resources2000–2002
Molecular Epidemiology Of Type 2 Diabetes In Mexican AmericansNational Center For Research Resources1999–2002
Effect Of Tight Glycemic Control On Glucose Phosphorylation &TransportNational Center For Research Resources1999–2002
Effect Of Prolonged Reduction Of Hyperinsulinemia On Glucose MetabolismNational Center For Research Resources1999–2002
Acute Effect Of Phlorizin On Plasma Glucose Levels &Hepatic GlucoseNational Center For Research Resources1999–2002
Insulin Effects On Glucose Transporters Of Human Peripheral TissueNational Center For Research Resources1993–2002
Effect Of Chronic Hyperinsulinemia On Glucose Phosphorylation And TransportNational Center For Research Resources1997–2000
Effect Of 2 Oral Contraceptives On Insulin Sensitivity In Women With IDDMNational Center For Research Resources1998–1999
Effect Of Elevated Plasma Free Fatty Acid Concentration On Glucose TransportNational Center For Research Resources1997–1999
Effect Of Miglitol On Glucose Metabolism In Normal And NIDDM SubjectsNational Center For Research Resources1996–1999
Metabolic And Molecular Basis Of NIDDMNational Center For Research Resources1996–1998
Regulation Of Glucose Phosphorylation And Transport In MuscleNational Center For Research Resources1997
Mechanisms Of Carbohydrate Intolerance In Patients With Gestational DiabetesNational Center For Research Resources1996–1997
Effect Of IGF-I On Glucose And Protein Metabolism In Control And NIDDM SubjectsNational Center For Research Resources1996
Effect Of Elevated Plasma Free Fatty Acid Levels On GluconeogenesisNational Center For Research Resources1996
Glucose Metabolism After Mixed Meal Ingestion In Diabetics And NormalsNational Center For Research Resources1993–1996
Effect Of Hyperglycemia On Rate Of Gluconeogenesis And GlycogenolysisNational Center For Research Resources1994
Carbohydrate Intolerance In Diabetes, Obesity, Uremia And HypertensionNational Center For Research Resources1994
Treatment Of Obesity With BromocriptineNational Center For Research Resources1993–1994
Leucine, Alpha-Ketoisocaproic Acid, And Insulin In Protein SynthesisNational Center For Research Resources1993–1994
Examination Of Effects Of Cardura On Glucose Metabolism In DiabeticsNational Center For Research Resources1993–1994
Effects Of Captopril And Nifedipine On Glucose Metabolism In DiabeticsNational Center For Research Resources1993–1994
Effect Of Misoprostol On Glucose Metabolism In Normal And NIDDM SubjectsNational Center For Research Resources1993–1994
Effect Of Metformin On Basal And Postprandial Lipid/Lipoprotein MetabolismNational Center For Research Resources1993–1994
Effect Of Lovastatin On Glucose And Lipid Metabolism In DiabeticsNational Center For Research Resources1993–1994
Effect Of IGF-1 On Glucose And Protein Metabolism In Control And NIDDM SubjectsNational Center For Research Resources1993–1994
Effect Of Bromocriptine On Glucose And Lipid Metabolism In DiabeticsNational Center For Research Resources1993–1994
Atherosclerotic Coronary Artery Disease And Insulin ResistanceNational Center For Research Resources1993–1994
Quantitative Role Of Glycolysis In Insulin-Mediated Glucose DisposalNational Center For Research Resources1990–1994
Insulin And Hyperaminoacidemia In Forearm Protein SynthesisNational Center For Research Resources1993
Glucagon Dose Response Curve For Hepatic Glucose ProductionNational Center For Research Resources1993
Effect Of Etomoxir On Glucose And Lipid Metabolism In DiabeticsNational Center For Research Resources1993
Combined Sulfonylurea/Insulin Therapy In Patients With NIDDMNational Center For Research Resources1993
Regulation Of Hepatic &Peripheral Glucose MetabolismNational Institute Of Diabetes And Digestive And Kidney Diseases1990–1993
Leucine Metabolism Normal, Diabetic, Obese And Uremic ManNational Center For Research Resources1990
Insulin Effects On Glucose Transport Of Human Peripheral TissueNational Center For Research Resources1990
Fenoldopam In Patients With Chronic Renal InsufficiencyNational Center For Research Resources1990
Combined Sulfonyurea/Insulin Therapy In PTS. With Non-Insulin Dependent D.M.National Center For Research Resources1990
Regulation Of Hepatic And Peripheral Glucose MetabolismNational Institute Of Diabetes And Digestive And Kidney Diseases1986–1988
Regulation Of Hepatic And Peripheral Glucose MetabolismNat Inst Of Arthritis, Diabetes, Digestive &Kidney Diseases1985

Committees

member, AACE/ACE Comprehensive Type 2 Diabetes Management Algorithm 2024
member, CONSENSUS STATEMENT BY THE AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY ON THE COMPREHENSIVE TYPE 2 DIABETES MANAGEMENT ALGORITHM 2016 EXECUTIVE SUMMARY

Professional Memberships

American Association of Clinical Endocrinologists - AACE
Member