Overview of the Endocrine
• System of ductless glands that secrete
– Hormones are “messenger molecules”
– Circulate in the blood
– Act on distant target cells
– Target cells respond to the hormones for which
they have receptors
– The effects are dependent on the programmed
response of the target cells
– Hormones are just molecular triggers
What the High Blood Pressure and
Blood pressure is the force of blood
against the walls of arteries.
Blood pressure rises and falls during the
When blood pressure stays elevated
over time, it is called high blood pressure.
The medical term for high blood pressure
“The Seventh Report of the Joint National Committee on
Prevention, Detection, Evaluation and Treatment of High
Blood Pressure defines hypertension as a blood pressure
exceeding 139/89 mm Hg for adults ages 18 years or older
on the mean of 2 or more properly seated BP readings on
each of 2 or more office visits.”
Hypertension is the most common public
health problem in developed countries
Called Silent Killer
No cure is available, but prevention and
management decrease the incidence of
hypertension and disease.
Prevalence on hypertension by age
Hypertension affects approximately 1 billion
85 % of hypertension is essential or idiopathic.
15 % have identifiable causes of secondary HTN.
Types of Hypertension
In ~80–95% of hypertensive patients are diagnosed as
having "essential" hypertension (also referred to as
primary or idiopathic hypertension).
In the remaining 5–20% of hypertensive patients, a
specific underlying disorder causing the elevation of
blood pressure can be identified.
In individuals with "secondary" hypertension, a
specific mechanism for the blood pressure elevation is
often more apparent. Renal disease is the most common
cause of secondary hypertension.
Hypertension : Symptoms
Most of the patients do not complain of any symptoms
Symptomatic patients may have one or more of the
- Severe shortness of breath
- Visual disturbances
- Nausea and vomiting
Causes of Secondary HTN
Renal Vascular Hypertension
Secrete catecholamines which can
produce severe HTN
10% arise outside the adrenal
10% of those in adrenal are bilateral
10% are malignant(to harm other)
10% arise in children
10% occur in association with other endocrine
Aldosterone and Hypertension
• Primary aldosteronism as described by Conn in 1955
had been thought to be an uncommon cause of
hypertension with prevalence of < 1% among
• Gordon et al in early 1990s screened 52 hypertensive
pts and found that 12% of the individuals were positive
for primary aldosteronism
• In a follow up study by Gordon evaluation of 199 pts
referred to a hypertension clinic found a prevalence of
primary aldosteronism to be at least 8.5%
Aldosterone and Hypertension
• Since the early studies by Gordon multiple
investigators have confirmed a prevalence of primary
aldosteronism of 5-15% in general selective
hypertensive population. Two studies in particular:
• Schwartz and Turner evaluated 118 pts with
hypertension and withdrew antihypertensive treatment.
Diagnosis of primary aldosteronism was made with 4
day salt load and lack of suppresion of aldosterone
• Primary aldosteronism was diagnosed in 13% of
• Results from
• Lipid reserves are
• Adipose tissue
cheeks & base of
Excessive aldosterone causes
low blood Ca2+
low blood renin
usually from cortical adenoma or hyperplasia
usually caused by impaired renal blood flow due to
renal artery stenosis from atherosclerosis
Renin (juxtaglomerular apparatus)
Angiotensinogen------> Angiotensin I
Angiotensin Converting Enzyme (pulmonary bed)
Angiotensin I ---------> Angiotensin II
Angiotensin II binds to specific receptors
#1. Angiotensin II binds to its receptors and
Inhibition of aldosterone secretion
Inhibits central sympathetic activity
Stimulates ACTH stimulation
Inhibits vasopressin release
Angiotensin II functions to maintain normal
extracellular volume and blood pressure
constricts vascular smooth muscle
release of Epinephrine and Norepinephrine
increases central sympathetic outflow
release of vasopressin
increases aldosterone secretion
Low renal perfusion sensed by JG
Low Na load to distal tubule sensed by
Upright posture increase CNS
All enhance renin secretion-->increased angiotensin II and
Feedback at multiple levels
renin release can be inhibited by high salt diet
and high blood pressure
Aldosterone secretion sensitive to both
potassium and sodium levels
The correct Approach to Hypertension
• Are all patients screened for hypertension?
Step1 • Are all hypertensives correctly identified?
• Are the correct drug combinations prescribed?
Step 2 • What is the compliance for medicines?
• Is the goal B.P. achieved and maintained?
Step 3 • Are there any complications/ side effects?