Why you should enter the Endocrinology Field

By Charles Chen, Aleem Malik, & Danny Yang

WHAT DO ENDOCRINOLOGISTS DO?WHAT DO ENDOCRINOLOGISTS DO?Most endocrinologists are specialized

internists, OB/GYN’s, or pediatriciansThey make diagnoses of a wide variety of

symptoms and variations and deal with disorders related to deficiency or excess of hormones.

They diagnose a variety of diseases

Different parts of the Endocrine SystemDifferent parts of the Endocrine SystemPituitary Gland

• Located inferior to the hypothalamus ; looks like a pea on a stalk• Secretes at least 9 hormones• Posterior lobe releases neurohormones• Anterior lobe releases adenohypophysis

Adenohypophyseal HormonesAdenohypophyseal Hormones • Melanocyte- stimulating hormone (MSH) CNS Neurotransmitter that controls

appetite• POMC- Source of two natural opiates• Growth Hormones- targets mainly bones and muscle• Thyroid-stimulating hormone (TSH)- Stimulates normal development and secretory activity of the thyroid gland• Adrenocorticotropic Hormone (ACTH)- stimulates the adrenal cortex to release corticosteroid hormones• Gonadotropins- Follicle-stimulating hormone (FSH) and luteinizing hormone (LH)o FSH stimulates gamete productiono LH promotes production of gonadal hormones; trigger ovulation• Prolactin (PRL)- protein hormoneo Produced by lactotrophs; stimulates milk production in breastso Estrogen stimulates prolactin (breast swelling during menstrual period)• Oxytocin- Released during childbirth, allows stretching of uteruso Hormonal trigger for milk ejection• Antidiueretic Hormone (ADH)- Prevents urine formation; helps the body avoid dehydrationo Releases when solute concentration in blood is too higho Alcohol inhibits ADH secretion

Thyroid GlandThyroid Gland• • Largest pure endocrine

• Located in the anterior neck on the trachea just inferior to the larynx• Thyroid Hormone (TH)- thyroxine(T4) and triiodothyronine (T3)o Affects virtually every cell in the bodyStimulates enzymes with glucose oxidation, increases basal metabolic rate and body heat production (calorigenic effect)• Calcitonin- Produced in C cells of the thyroid glando Inhibits osteoclast activity o Only important in childhood

Parathyroid Gland• Parathyroid hormone (PTH) is the single most important hormone controlling the calcium balance of the blood.o PTH is released by falling blood Ca2+ levels and inhibited by hypercalcemia o Precise control of Ca2+ is critical for nerve impulses, muscle contraction and blood clotting

Adrenal (Suprarenal) Glands• Sits on top of kidneys• Corticosteroids• Mineralocorticoidso Aldosterone- maintain sodium ion balance• Glucocorticoidso Influence the energy metabolism of most body cells and help us to resist stressorso Maintain blood glucose levels• Gonadocorticoids (Sex hormones)o Testosterone and estrogen

Pancreas • Glucagon- extremely potent hyperglycemic agento Breakdown glycogen to glucoseo Synthesis of glucose from lactic acido Release of glucose to the blood by liver cells• Insulin- lowers blood glucose levelso Inhibits the breakdown of glycogen to glucoseo After glucose enters a target cell, insulin binding triggers enzymatic activities that1. Catalyze the oxidation of glucose for ATP production2. Join glucose molecules together to form glycogen3. Convert glucose to fatGonads• Male and female gonads produce steroid sex hormones• Testosterone and estrogen are responsible for the maturation of reproductive organso Produced in the testes and ovaries

Pineal Gland• Hangs from the roof of the third ventricle in the diencephalon o Melatonin-sleep hormoneAffects the timing of pubertyThymus• Part of the immune system- diminishes in size with age

The effects of illicit drugs, alcohol, and The effects of illicit drugs, alcohol, and tobacco on the endocrinetobacco on the endocrineSHS exposure contributes to disruptions in

thyroid functionSmoking has multiple effects on pituitary,

thyroid, and adrenal glands; testicular and ovarian function

Alcohol’s affects hormone synthesis, storage and release; hormone transport in plasma /proteins; and effects on hormone receptors and second messenger systems

Alcohol affects production of hormones such as progesterone and estrogen, and alters the amounts of hormones produced during the menstrual cycle

Cocaine inhibits Prolactin secretionTHC appears to depress prolactin, thyroid

gland function, and growth hormone while elevating adrenal cortical steroids

Effects of endocrine malfunctionEffects of endocrine malfunction Adrenal Gland: Function 1. The adrenal medulla is responsible for releasing hormones such as

adrenaline into the blood stream. The adrenal cortex produces and releases other types of hormones that control how the body makes use of fats, carbohydrates and proteins. The adrenal cortex is also responsible for the production of the male hormone testosterone in both men and women, as well as the production of the hormone mineralocorticoids. Mineralocorticoids control blood pressure and levels of potassium and salt.

Removal 2. Although the adrenal glands produce important hormones, it is possible to

remove one or both and maintain some degree of a normality. The removal of one or both of the adrenal glands is called an adrenalectomy. Living with one adrenal gland is possible without the use of hormonal supplements. But hormonal supplements are usually required when both adrenal glands are removed.

Effects of Complete Removal 3. Partial or complete adrenal gland removal is only done

in cases of adrenal cancer. Therefore, the patient must be prepared to deal not only with the drop in essential hormone production, but also with the side effects of chemotherapy and/or radiation treatment.

To replace the hormonal production of the adrenal glands, a patient is often placed on hormone replacement therapies. Without this type of hormone replacement, the patient can develop other major health problems, such as diabetes, obesity, high-blood pressure and other symptoms of a nonfunctioning metabolism. Despite hormone replacement, radiation and chemotherapy, the prognosis for five-year survival is not positive. Statistics show that 65 to 90 percent of those who have received treatment will still die within five years.

Pancreas: If your pancreas malfunctions (cancer) or your

pancreas is removed, then you die.Thyroid:Removal of the thyroid gland results in death because

it regulates calcium which messes up your body.Pineal:Removal of the pineal gland and reduction in

melatonin output have been implicated in the increased incidence of breast cancer (laboratory animals). Patients with breast cancer often exhibit lower levels of melatonin – also shown to be protective against genetic damage and stimulates the immune system.

Pituitary: With removal of pineal gland, these things do not happen,

probably resulting in death. Growth Blood Pressure Some aspects of pregnancy and childbirth including stimulation of

uterine contractions during childbirth Breast Milk production Sex Organ functions in both men and women Thyroid Gland function The conversion of food into energy (metabolism) Water and osmolarity regulation in the body Secretes ADH (antidiuretic hormone) to control the absorption of

water into the kidneys Temperature regulation