Abstract Background: Salt is an important component for normal function of cells. However, we consume more than 10 times the salt that is required. This high salt content affects the renin–angiotensin–aldosterone system (RAAS) that regulates blood pressure (BP) and water content of our body. Angiotensinogen is an oligopeptide hormone precursor serving as a substrate for renin in the formation of angiotensin I. Angiotensin I is converted to angiotensin II that causes vasoconstriction and a subsequent increase in BP. We hypothesized that angiotensinogen secretions increases in the kidney and urine with intake of high salt diet. Methods: Dahl salt sensitive (SS) and salt resistant (SR) male rats (8 weeks old) were fed with high salt (HS) and low salt (LS) diet along with or without aldosterone (ALDO); aldosterone antagonist, eplerenone (EPL); and NADPH oxidase inhibitor, apocynin (APC) for 21 days. Urine samples and kidney were collected; total proteins isolated, and quantified using the microassay procedure and analyzed by western blot for angiotensinogen. Results: Angiotensinogen was detected in the kidney samples of Dahl SS rat when fed either low or high salt diet, whereas angiotensinogen was detected in kidney samples of Dahl SR rats when fed with high salt diets. Angiotensinogen was not detected in urine samples. Conclusions: In conclusion, consuming a high salt diet increases Angiotensinogen that lead to an increase in angiotensin II which may cause an increase in BP. Acknowledgements: Vivien Thomas Summer Research Program, Morehouse School of Medicine, Atlanta, GA, USA.

1. EFFECTS OF EXCESS SALT
DIET ON ANGITENSINOGEN
SECRETIONS IN THE KIDNEY
OVER TIME
Chieh-Yin Kuo,
Vivien Thomas Summer Research Program;
Department of Pharmacology & Toxicology,
Morehouse School of Medicine, Atlanta.

2. SALT (SODIUM CHLORIDE, NACL)
INTAKE
• Add flavor to our food.
• Adults need ~6g (or around about a teaspoon) of salt a
day.
• According to the World Health Organization (WHO), the
current global average intake of salt is between 9g and
12g per day or more.

3. KIDNEY
 An essential organ in the urinary system
 Serve for homeostatic functions
(the regulation of electrolytes, maintenance of acid–base
balance, and regulation of blood pressure via maintaining salt
and water balance)

4. KIDNEY DISEASES
 Kidney removes waste products from blood and regulate the
water fluid
 High salt diet reduce function and removed less water in the
kidney. This result in high blood pressure (BP) and kidney
disease .
 African American are 3-5 times more likely to suffer kidney
failure than Caucasian.
 African American with diabetes are 10 times more likely to
have kidney failure.

5. ANGIOTENSINOGEN
 Oligopeptide hormone precursor serving as a
substrate for renin in the formation of angiotensin I
 Angiotensinogen produced in liver
 Causes vasoconstriction and a subsequent increase in
blood pressure.

6. RENIN- ANGIOTENSINOGEN
 Renin, which is primarily released by the kidneys, stimulates the
formation of angiotensin in blood and tissues, which in turn
stimulates the release of aldosterone from the adrenal cortex.
Dr Bayorh’s lab has
previously shown that a HS
diet increases Angiotensin II.
My job was to see if HS diet
increases Ang II by
increasing
Angiotensinogen.

7. RENIN- ANGIOTENSINOGEN
 Acts on the adrenal cortex to release aldosterone, which in turn
acts on the kidneys to increase sodium and fluid retention
 Stimulates the release of vasopressin (antidiuretic hormone,
ADH) from the posterior pituitary, which increases fluid retention
by the kidneys
 Stimulates thirst centers within the brain

8. HYPOTHESIS
 We hypothesized that angiotensinogen secretion
increases in the kidney and urine with high salt diet.

9. METHODS
Dahl salt sensitive (SS) rat and salt resistance (SR) rats (8 weeks old)
were divided into following groups and treated as mentioned below
for 21 days.
 Group 1 : low salt (0.3% NaCl) control
 Group 2 : high salt (8% NaCl) diet
 Group 3 : low salt diet + aldosterone (ALDO; 0.2 mg pellet)
 Group 4 : high diet + aldosterone (ALDO; 0.2 mg pellet)
 Group 5 : high diet + apocynin (APC, 1.5 mM in the drinking water)
 Group 6 : high diet + Eplerenone (EPL)
Apocynin, is a NADPH oxidase inhibitor; blocks the bad effects of angiotensin II
Eplerenone, is an aldosterone antagonist; blocks the effects of aldosterone

10. METHODS
 Microassay Procedure was used to analyzed total protein
content in the urine sample of rats.

11. WESTERN BLOT (WB)-TOTAL PROTEIN
SEPARATION
USING SDS-PAGE

12. WESTERN BLOT (WB)-TRANSFER OF PEPTIDE
TO PBDF MEMBRANE

13. RESULT
S
Normal rat :
Average systolic pressure = 121 mmHg; Average diastolic pressure = 84 mmHg;
Average mean pressure = 103 mmHg; Heart rate = 380 beats per minute

14. RESULT
S

15. RESULTS-
WESTERN BLOT ANALYSIS ON
ANGINOTENSINOGEN
Rat Urine Sample

16. RESULTS-
WESTERN BLOT ANALYSIS ON
ANGINOTENSINOGEN
Additional analysis required to better understand the results above.

17. CONCLUSIONS
 These findings suggest that consuming high salt
diets increase Angiotensinogen that leads to an
increase in Angiotensin II which may cause an
increase in blood pressure.

18. Take Home Message
Key messages to protect kidney health
• Become a label reader
• Take every day fresh fruits and vegetables as a major part of diet
• Avoid fast foods and processed food
• Drink more water

19. Future goal
• Increase the number of samples for this
study.
• Also, examine how high salt diet affects
kidney functions.

20. ACKNOWLEDGEMENT
 Dr. Danita Eatman
 Dr. Mohamed A. Bayorh
 Mrs. Aisha Rollins-Hairston
 Ms. Nithya Rajendran
 Ms Raeonda Williams
 Mrs. Wanda Harvey
 Vivien Thomas Summer Research Program,
Morehouse School of Medicine, Atlanta.

21. RESOURCES
 http://www.news-medical.net/news/20120521/Salt-intake-why-is-it-bad-
for-you.aspx
 http://pcwww.liv.ac.uk/~petesmif/petesmif/why%20do%20we%20need
%20kidneys/the%20kidney%20and%20homeostasis.htm
 http://totalhealthforall.com/physical-health-fitness/salt-the-silent-killer-
also-known-as-white-death/