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Chapter 17
The Endocrine System and
Drug Therapy
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Chapter 17
Topics
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Anatomy and Physiology of the Endocrine System
Diabetes
Thyroid Disorders
Adrenal Gland Disorders
Herbal and Alternative Therapies
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Anatomy and Physiology of the Endocrine System
The Endocrine System
• A collection of glands in various parts of the body that
produce hormones that regulate bodily functions
 Hormones are secreted substances that regulate
metabolism, growth, and fluid balance in various ways
• A negative feedback system regulates hormone release;
often is a series of hormones, with one activating the next
 As more hormones are released into the bloodstream,
receptors detect the rise in concentration of the
hormone and signal the gland to slow production
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Anatomy and Physiology of the Endocrine System
Pituitary Gland
• It controls other endocrine glands and bodily functions
• Part of the hypothalamic-pituitary axis
• Pituitary gland plays a key role in growth, onset of puberty,
and reproduction cycles
 Core feedback mechanism that controls endocrine
function
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Anatomy and Physiology of the Endocrine System
Pituitary Gland
• This gland
stimulates other
glands in the
endocrine system
to release
hormones into
the bloodstream
• These hormones
trigger responses
in target tissues
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Anatomy and Physiology of the Endocrine System
Thyroid Gland
• It releases T3 and T4 in response to TSH released from the
pituitary gland
• T3 controls most of the physiological action
• Both T3 and T4 regulate basal metabolic rate and affect
metabolism of carbohydrates, fats, and proteins
• Thyroid hormones increase conversion of food to energy
which raises body temperature
 Iodine is required for formation of thyroid hormones
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Anatomy and Physiology of the Endocrine System
Adrenal Glands
• Glands are located on top of the kidneys
• Adrenal cortex (outer layer) releases corticosteroids
 Mineralocorticoids regulate fluid and electrolyte
balance
 Glucocorticoids affect day/night cycles and metabolism
• Adrenal medulla (inner layer) produces adrenaline
(epinephrine)
 Adrenaline increases blood pressure, diverts blood
from organs to muscles, releases stored glucose and fat
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Anatomy and Physiology of the Endocrine System
Adrenal Glands
(continued)
• Adrenaline readies
the body for “fight or
flight”
• It can give someone
tremendous strength
or speed when
encountering a fearful
situation
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Anatomy and Physiology of the Endocrine System
Hypothalamus
• Hypothalamus produces corticotropin-releasing factor that
stimulates the pituitary gland to make ACTH
• ACTH stimulates adrenal glands to release cortisol (the
primary glucocorticoid) in a circadian rhythm
• Cortisol affects glucose metabolism, fat deposition, water
retention, and anti-inflammatory action of the immune
system
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Anatomy and Physiology of the Endocrine System
Pancreas
• It produces and releases digestive enzymes into intestine
• Alpha islet cells of pancreas produce glucagon, which
 activates liver cells to break down stored glycogen into
glucose and release it into the blood
 raises blood glucose levels
 facilitates breakdown of fats and proteins into
alternative sources of energy, producing ketones
• Beta islet cells of pancreas produce insulin, which
 is released in response to a rise in blood glucose
 allows glucose to enter cells and provide energy
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Anatomy and Physiology of the Endocrine System
Normal Glucose
Metabolism
• The pancreas
releases insulin
after eating to
lower blood
glucose and
releases glucagon
when fasting to
maintain
adequate blood
glucose
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Anatomy and Physiology of the Endocrine System
Blood Glucose
Levels
• Various
hormones
produced in the
endocrine
system maintain
blood glucose
levels after
eating and
between meals
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Diabetes
About Diabetes Mellitus
• Diabetes is elevated blood glucose that results in damage
to small blood vessels and nerve tissue
 It has significant and life-threatening effects
• Three types: Type 1, Type 2, and gestational diabetes
Type 1 Diabetes
• Least common type; affects about 10% of patients with
diabetes (sometimes called juvenile diabetes)
• Autoimmune process impairs body’s ability to make insulin
• Without insulin, glucose climbs to dangerous blood levels;
body uses alternative energy sources, producing ketones
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Diabetes
Type 1 Diabetes
• In the absence of
insulin, ketones
accumulate to toxic
levels in the blood,
producing a lifethreatening
emergency called
ketoacidosis
• Therefore, insulin is
given to patients with
Type 1 diabetes
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Diabetes
Type 2 Diabetes
• A multifactorial disorder causing high blood glucose;
accounts for around 90% of patients with diabetes
• It begins with central obesity (accumulation of abdominal
fat) that causes insulin insensitivity
 Pancreas still makes insulin, but the insulin does not
work as well
• Insulin insensitivity triggers overproduction of glucagon,
which increases blood glucose
• Beta cells try to produce more insulin but can’t keep up
• First treated with oral agents; eventually insulin is needed
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Diabetes
Type 2 Diabetes
(continued)
• Progressive disease
that causes insulin
insensitivity,
impaired insulin
production, and
altered glucagon
release
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Diabetes
Type 2 Diabetes: Metabolic Syndrome
• Many patients with Type 2 diabetes have metabolic
syndrome
• Condition refers to a triad of problems: high BP, high
cholesterol and triglycerides, and high blood glucose
• Patients may not have high blood glucose all of the time
 May have impaired fasting glucose or impaired glucose
tolerance
• Condition puts patients at high risk for cardiovascular
disease
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Diabetes
Gestational Diabetes
• Insulin resistance caused by excess hormones produced
during pregnancy; preserves glucose for developing fetus
• It mimics Type 2 diabetes and often precedes it
Symptoms of All Types of Diabetes
• Common: increased urination (polyuria), excessive
urination at night (nocturia), glucose in the urine
(glycosuria), thirst (polydipsia), hunger (polyphagia),
blurred vision, fatigue
• Other: frequent infections, slow wound healing, weight
gain or loss, numbness and tingling in fingers and toes
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Diabetes
Risk Factors for Developing Type 2 Diabetes
• Age over 45 years
• Family history of diabetes
(parents/siblings)
• Overweight (BMI over 25
kg/m2)
• Hypertension (BP over
140/90 mmHg)
• Low HDLs and high
triglycerides
• History of gestational
diabetes or birth of baby
• Habitual physical inactivity
over 9 pounds
• Race/ethnicity
• Polycystic ovary syndrome
• Impaired fasting glucose or
glucose intolerance
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Diabetes
Untreated Diabetes: Microvascular Complications
• Nephropathy: damage to kidneys, affecting their ability to
filter the blood
 If untreated, can lead to kidney failure and transplant
• Neuropathy: damage to tiny nerves in the extremities; in
the feet, loss of sensation can lead to ulcers
 If untreated, can lead to infection and amputation
• Retinopathy: damage to retinal tissue in the eyes
 If untreated, can progress to blindness
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Diabetes
Untreated Diabetes: Macrovascular Complications
• Macrovascular complications for Type 2 diabetes
 Heart disease
 Heart attack
 Patient with diabetes half as likely to survive as
someone without diabetes
 Strokes
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Diabetes
Hypoglycemia
• Low blood glucose or low blood sugar reaction
• Commonly results from injecting too much insulin or
skipping meals when taking medication for diabetes
• Symptoms: shakiness, dizziness, sweating, headache,
irritability, confusion, vision changes, hunger
• If have symptoms, test blood glucose and consume
simple sugar right away
 15–30 g of carbohydrate such as nondiet soda, juice,
hard candy, glucose tablets
Do not ingest large amounts of food
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Diabetes
Measuring Blood Glucose
• Diabetes is detected by measuring blood glucose (sugar)
concentrations via lab blood tests or fingerstick at home
• Blood glucose levels
 Normal: 70–120 mg/dL
 Indicative of diabetes: 200 mg/dL or greater or a fasting
result (8+ hours since eating) of 126 mg/dL or greater
• Glucose meters
 Available for home use; technicians can help patients
with selection and demonstration
 Goal is to maintain blood glucose within normal range
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Diabetes
Measuring Blood Glucose: Hemoglobin A1C Test
• Test used to assess overall blood glucose control
• Measures the percentage of RBCs with glucose stuck to the
hemoglobin molecules contained inside
 Glucose binds to hemoglobin for life of RBCs (3 months)
 This test provides an overall average of glucose
concentration over the previous 3 months
• Normal range for an A1C is 4–6%; patients with untreated
diabetes can have an A1C of 10% or greater
• The test can be run via a blood draw in the laboratory or
fingerstick technology in a clinic or pharmacy setting
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Diabetes
Drugs for Diabetes
• Drug therapy treats but does not cure disorder
• Treatment for Type 1 diabetes is insulin
• Initial treatment for Type 2 diabetes is lifestyle changes
 Reduction of carbohydrate, fat, and calorie intake;
regular exercise; smoking cessation; weight loss
• Drug therapy for Type 2 diabetes begins with metformin,
followed by combination therapy, and eventually leading
to insulin
 Insulin is required to achieve goals for blood glucose
and A1C
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Your Turn
Question 1: What is the function of glucose in the body?
Answer: Glucose provides the energy for all the cells in the
body to live.
Question 2: A patient who has Type 2 diabetes has made various
lifestyle changes. She has lost excess weight, watches her
carbohydrate and fat intake, and exercises most days. What is
likely to happen next?
Answer: Because Type 2 diabetes is progressive, the patient
will eventually need drug therapy, beginning with metformin.
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Diabetes
Drugs for Diabetes: Metformin
• Indication (initial): Type 2 diabetes, alone or in
combination with other agents
• Mechanism of Action: inhibits excess hepatic glucose
production, increases insulin sensitivity in body tissues
• Route: all are oral; take with food or milk
• Side Effects (common): stomach upset, abdominal cramps,
nausea, diarrhea, flatulence, metallic taste
• Side Effects (severe, rare): lactic acidosis (potentially fatal)
• Cautions: Contraindicated in patients with kidney
dysfunction, liver problems, heart failure
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Diabetes
Drugs for Diabetes: Insulin Secretagogues
• Two classes: sulfonylureas and glinides
• Indication (sulfonylureas and glinides): Type 2 diabetes,
alone or in combination with other agents
• Mechanism of Action: stimulate insulin production from
the pancreas to directly lower blood sugar
• Route: all are oral; different onsets and durations of action
 Sulfonylureas: 30 minutes or more to start working, last
8 hours or longer
 Glinides): 10 minutes to start working, last for about 2
hours
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Diabetes
Drugs for Diabetes: Insulin Secretagogues
(continued)
• Side Effects (common): hypoglycemia
• Side Effects (other): nausea, diarrhea, constipation
• Cautions: patients should know the symptoms of low
blood sugar and how to treat it; monitor regularly
• Cautions: patients with liver or kidney disease may not be
able to take sulfonylureas
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Diabetes
Drugs for Diabetes: Thiazolidinediones
• Also called glitazones or TZDs
• Indication: Type 2 diabetes, used in combination with
metformin or sulfonylureas
• Mechanism of Action: cause increased production of
insulin receptors to increase insulin sensitivity in body
• Route: all are oral; onset varies (weeks or months)
• Side Effects (common): fluid accumulation (edema),
weight gain
• Side Effects (severe, rare): liver toxicity, macular edema
• Caution: patients with heart failure should not take TZDs
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Diabetes
Drugs for Diabetes: Incretin Therapies
• Indication: Type 2 diabetes, in combination with
metformin or sulfonylureas
• Mechanism of Action: either mimic endogenous incretin
hormones or change their metabolism to increase activity
• Route: SC or oral
• Side Effects (GLP-1, common): nausea, vomiting, diarrhea,
dizziness, fatigue, headache
• Side Effects (DPP-4 inhibitors, common): headache,
nasopharyngitis, upper RTIs
• Caution: refrigerate injectables until dispensed or used
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Diabetes
Drugs for Diabetes: Insulin
• Indication (Type 1): combination of basal and bolus insulin
• Indication (Type 2): same as Type 1 or an injection of longacting insulin at bedtime added to oral medications
• Four types of insulin: rapid-acting, short-acting,
intermediate-acting, long-acting (see Table 17.6)
• Route: SC injection only; self-injections used
 Abdomen is preferred injection site due to consistent
rate of absorption into blood
 Insulin available in vials (for syringes) and self-injector
pen devices; patients must be instructed on use
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Diabetes
Drugs for Diabetes: Insulin (continued)
 Insulin pumps also available; deliver insulin through a
tiny tube just under the skin
• Side Effects (common): serious hypoglycemia
• Side Effects (severe): diabetic coma if blood glucose levels
are lower than 40 mg/dL
 Diabetic coma (loss of consciousness and brain
damage) is a medical emergency
• Caution: insulin should be refrigerated until
dispensed or used; do not use if insulin clumps or
looks frosty
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Diabetes
Drugs for Diabetes: Alpha-Glucosidase
Inhibitors
• Indication: adjunctive treatment for Type 2 diabetes, but is
limited by side effects
• Mechanism of Action: inhibit digestion of carbohydrates
within the GI system, which reduces glucose absorption
• Route: oral; taken with first bite of each meal to keep
carbohydrates in the food from entering the bloodstream
in high amounts
• Side Effects (common): abdominal pain, gas, bloating,
diarrhea
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Thyroid Disorders
Hypothyroidism
• Too little thyroid hormone is produced (more common
than hyperthyroidism)
• Causes: pituitary or hypothalamus dysfunction, removal of
thyroid, Hashimoto’s disease; radioactive iodine therapy
• Symptoms: constipation, bradycardia, dry skin, tremors,
weight gain, cold intolerance, depression, fatigue, reduced
mental acuity, memory loss
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Thyroid Disorders
Hyperthyroidism
• Too much thyroid hormone is produced
• Causes: Graves’ disease, thyroid nodules or tumors,
pituitary nodules or tumors
• Symptoms: diarrhea, skin flushing, nervousness, insomnia,
hyperactivity, heat intolerance, tachycardia, weight loss
• Sign: exophthalmos (fat collects behind the eyeball,
causing protrusion and inability for eyelids to fully close)
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Thyroid Disorders
TSH and the Hypothalamic-Pituitary Axis
• TSH is the lab test
used to monitor
thyroid disorders
• TSH, released by
the pituitary gland,
stimulates thyroid
to make T3 and T4
• High TSH results
means that T3 and
T4 are low
(hypothyroid)
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Thyroid Disorders
Drugs for Thyroid Disorders
• Treatment for hypothyroidism involves oral thyroid
hormone supplementation
• Treatment for hyperthyroidism involves
 Surgery to remove or reduce the malfunctioning gland
or ablation (destroys thyroid via radioactive iodine)
 Afterward, oral thyroid supplementation is given to
artificially provide adequate hormone levels
• Route: daily oral doses; doses are individualized to each
patient using blood tests to measure hormone levels
 Each tablet strength of thyroid hormone is color-coded
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Thyroid Disorders
Drugs for Thyroid Disorders (continued)
• Side Effects (common): usually related to therapeutic
overdose; patient exhibits hyperthyroid symptoms such as
heart palpitations, elevated BP, fever, tremors, headache
• Side Effects (long-term overdosage): loss of bone density
and impaired fertility; for gross overdosing, cardiac arrest
• Caution: when filling thyroid hormone products, use the
same product for the same patient for each refill
 Do not switch between brands and generic forms
 Various brands may contain slightly different amounts,
enough for changes to be felt by individual patients
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Your Turn
Question 1: A patient who has diabetes is taking insulin. Because
he is very busy at work, he decides to skip breakfast and lunch.
Now he feels like he might pass out. His blood glucose
concentration is 40 mg/dL. What will likely happen next?
Answer: The patient may be experiencing a diabetic coma,
requiring emergency care.
Question 2: How is drug therapy for hypothyroidism and
hyperthyroidism alike?
Answer: In hypothyroidism, thyroid hormone
supplementation is accomplished with the same oral
medications as used after thyroid removal or ablation in
hyperthyroidism.
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Adrenal Gland Disorders
About Adrenal Gland Disorders
• Disorders can be categorized by either the overproduction
or the underproduction of hormones
• Two types of adrenal gland disorders include Addison’s
disease and Cushing’s disease
Addison’s Disease
• Deficiency (underproduction) of glucocorticoids and
mineralocorticoids; this condition can be serious
• Symptoms: weakness; hyperkalemia, hyperpigmentation
of skin, low blood sodium and glucose, low BP, weight loss
• Treatment: oral corticosteroids
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Adrenal Gland Disorders
Cushing’s Disease
• Overproduction of steroid hormones; often caused by
tumors in the adrenal glands, but overmedication with
corticosteroids is also a cause
• Symptoms: moon face, abdominal weight gain, buffalo
hump, osteoporosis, mood changes, hypertension,
cataracts, PUD
• Normal sleep and wake cycles may also be affected
• Treatment: surgery to remove tumors; sometimes
cytotoxic drug therapy
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Herbal and Alternative Therapies
• Chromium
 An essential trace element used for diabetes
prevention and treatment
 Patients with diabetes have a chromium deficiency
 Patients with kidney or liver disease should avoid
• Cinnamon
 Taken for Type 2 diabetes
 Research shows that it has minimal effects on
blood glucose
 Patients with liver diseases should avoid
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Summary
• The endocrine system regulates metabolism, growth, and
fluid in various ways
• Insulin is used exclusively to treat Type 1 diabetes
• Type 2 diabetes is treated with oral agents first; most
patients need insulin at some point
• Metformin, sulfonylureas, TZDs, and incretins are oral
agents used to treat Type 2 diabetes
• Oral thyroid hormones are used to treat hypothyroidism
• Addison’s disease and Cushing’s disease are adrenal gland
disorders
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