The Endocrine System

Different hormones, different signals

Anteriorpituitary

Thyroidgland

TSHThyroid

hormones

Negative feedback -

+

Hypo-thalamus

Waterabsorption

ADHosmolality

Negative feedback -

+

Pancreas

Liver, fat& muscle

InsulinGlucose

Negative feedback -

+

Para-thyroids

Bone, GIT& Kidney

PTHcalcium

Negative feedback -

+

Growth Hormone

• Release of GH is stimulated by the release of GHRF secreted by the hypothalamus

• GH is inhibited by – Glucocorticoids– Obesity– Depression– Progesterone– Hypokalemia– Altered thyroid function

Hormones of pituitary gland

Deficit of GHDeficit of GH

Overproduction of GHOverproduction of GH

Posterior pituitary hormonesPosterior pituitary hormones

Synthetic Human Growth Hormones

• somatrem (Protropin)• somatropin (Humatrope)

Drug List

Growth Hormone

• The younger the patient at time of treatment the greater the height that may be achieved

• Little response is seen after age 15-16 in boys and 14-15 in girls

Thyroid Gland• Produces hormones (T3 and T4) that

stimulate metabolic activity of body tissues• Hypothalamus and pituitary glands work

together to release TSH• TSH stimulates T3 and T4 release

Thyroid Hormone Feedback Loop

• Thyroid hormones build up in the blood• Signals are sent to the hypothalamic-

pituitary axis that adequate levels have been met

• TSH levels decrease

FeedbackAnteriorpituitary

Thyroidgland

TSHThyroid

hormones

Negative feedback -

+

Hypothyroidism

• Production of thyroid hormones is below normal

• Cretinism occurs in children at birth due to inadequate maternal iodine intake– Can cause mental retardation, thick tongue,

lethargy, lack of response, short stature – can be corrected if treated

Primary and secondary disorders

PrimaryThyroiddisease

SecondaryThyroiddisease

Hypothyroidism Symptoms

• Apathy• Constipation• Decreased heart rate• Depression• Dry skin, nails, and

scalp• Easy fatiguing• Enlarged thyroid

• Lowered voice pitch• Myxedema• Puffy face• Reduced mental acuity• Swelling of eyelids• Tongue enlarged and

thickened• Weight gain

Struma (goiter) and Struma (goiter) and hyperthyroidismhyperthyroidism

HypothyroidismHypothyroidism

ThyrotoxicosisThyrotoxicosis

Congenital hypothyroidismCongenital hypothyroidism(physical and mental retardation – (physical and mental retardation –

nanism - pygmy, idiotismnanism - pygmy, idiotism

Causes of Hypothyroidism

• Autoimmune destruction of the gland

• Radioactive iodine therapy

• Surgical removal of the gland

Agents for Hypothyroidism

• levothyroxine, T4 (Levothroid, Levoxyl, Synthroid)

• liothyronine, T3 (Cytomel)• liotrix (Thyrolar)• thyroid (Armour Thyroid)

Drug List

levothyroxine, T4 (Levothroid, Levoxyl, Synthroid)

• Used for chronic therapy

• Can be cardiotoxic

• Alters protein binding of other drugs

• Should not switch brands once stabilized

levothyroxine Dispensing Issues

• Can be cardiotoxic; report any of the following:– Chest pain, increased pulse, palpitations, heat

intolerance, excessive sweating

Warning!

levothyroxine Dispensing Issues

• Look-alike and Sound-alike Drugs:– levothyroxine (thyroid replacement)– levofloxacin (antibiotic)

Warning!

Hyperthyroidism• Excessive thyroid hormone• Most common cause is

Grave’s disease• Other causes:

– Excessive exogenous iodine– Thyroid nodules– Tumor in the pituitary causing

overproduction of TSH

Symptoms of Hypterthyroidism• Decreased menses• Diarrhea• Exophthalmos• Flushing of the skin• Heat intolerance• Nervousness• Perspiration• Tachycardia• Weight loss

Agents for Hyperthyroidism

• methimazole (Tapazole)• propylthiouracil, PTU • radioactive iodine, 131I

Drug List

Hypoglycemic Agents

• In the islets of Langerhans, in the pancreas, there are two primary specialized cells

• Alpha Cells– Produce glucagon and raise blood glucose levels

• Beta Cells

Hypoglycemic Agents

• In the islets of Langerhans, in the pancreas, there are two primary specialized cells

• Alpha Cells– Produce glucagon and raise blood glucose levels

• Beta Cells– Produce insulin and lower blood glucose levels

Insulin

• Helps cells burn glucose for energy• Works with receptors for glucose uptake• Enhances transport and incorporation of

amino acids into protein• Increases ion transport into tissues• Inhibits fat breakdown

Insulin

• Administered subcutaneously due to degradation in the GI tract

• Different types of insulin have different onset of action times and duration of action times

Insulin Duration of Action

Type Duration of Action

Humalog, Novolog

1 hr (works in 15 mins and gone in about an hour)

Regular 5-6 hours (onset – 30 mins)

NPH 10-16 hours

Lente 12-18 hours

Lantus 24 hours

mixed Quick onset, longer duration

Insulin Dispensing Issues

• It is very easy to grab the wrong insulin in the refrigerator

• Always double-check yourself• They look exactly alike

Warning!

Insulin administration sites should be rotated

Hypoglycemia

• Blood glucose levels of <70 mg/dL• Can be caused by

– Skipping meals– Too much exercise– Poor medication regimen– Certain drugs

Signs & Symptoms of Hypoglycemia

• Confusion• Double vision• Headache• Hunger• Numbness and

tingling in mouth and lips

• Nervousness• Palpitations• Sweating• Thirst• Visual disturbances• Weakness

insulin glargine (Lantus)

• Synthetic long-acting insulin• Absorbed slowly and works over a 24-hour

time period• Works similarly to physiologic insulin

release

Human InsulinsMixtures

• insulin aspart w/ protamine-insulin aspart (NovoLog Mix 70/30)

• insulin lispro w/ protamine-insulin lispro (Humalog Mix 75/25)

• insulin with zinc (lente) (Humulin L)• NPH-regular insulin (Humulin 70/30)

Drug List

Oral Hypoglycemic Agents First- Generation

Sulfonylureas

• chlorpropamide (Diabinese)• tolbutamide

Drug List

Oral Hypoglycemic AgentsSecond-Generation

Sulfonylureas

• glimepiride (Amaryl)• glipizide (Glucotrol, Glucotrol XL)• glyburide (DiaBeta, Glynase, Micronase)

Drug List

Oral Hypoglycemic Agents

Enzyme inhibitors:• acarbose (Precose)• miglitol (Glyset)Biguanide:• metformin (Glucophage, Riomet)

Drug List

Oral Hypoglycemic Agents Combinations

• glipizide-metformin (Metaglip)• glyburide-metformin (Glucovance)• rosiglitazone-metformin (Avandamet)

Drug List