Endocrinology is the study of hormones, which act as chemical "messengers" to tissues and organs.

Hormones influence a range of body activities, including:

  • Alertness Levels
  • Appetite Regulation
  • Blood Sugar Regulation
  • Bone Growth
  • Metabolism (food burning and waste elimination)
  • Puberty
  • Reproduction

Hormones are created in glands, which are organs that make up the body's endocrine system. When hormones don't work correctly, the malfunction leads to problems such as:

  • Appetite Disorders and Obesity
  • Bone Issues
  • Cancer
  • Diabetes
  • Neurological Disorders
  • Pituitary Conditions
  • Sexual Problems
  • Thyroid Conditions


Endocrinologists (doctors who specialize in endocrinology) finish four years of medical school and then spend 3-4 years in an internship and residency program. These specialty programs cover internal medicine, pediatrics, or obstetrics and gynecology. They spend up to three more years learning how to diagnose and treat hormone conditions. 

To learn more about endocrinologists on staff at Christian Hospital, call 314.747.WELL (314.747.9355) or toll-free 877.747.9355 or search online >

The Endocrine System

Adrenal Glands

  • Secrete hormones that influence the body's metabolism, blood chemicals, and body characteristics
  • Influence part of the nervous system involved in the response and defense against stress


  • Activates and controls the part of the nervous system that controls involuntary body functions, the hormonal system and many body functions
  • Helps regulate sleep and stimulates appetite

Ovaries and Testicles

  • Secrete hormones that influence female and male characteristics


  • Secretes a hormone (insulin) that controls the use of glucose by the body

Parathyroid Glands

  • Secrete a hormone that maintains the calcium level in the blood

Pineal Body

  • Involved with daily biological cycles

Pituitary Gland

  • Produces a number of different hormones that influence other endocrine glands

Thymus Gland

  • Plays a role in the body's immune system

Thyroid Gland

  • Produces body heat
  • Stimulates bone growth
  • Fuels body metabolism

Common Endocrine Diseases and Disorders

Hormones protect bone tissue; when these hormone levels are too low, bones lose calcium and begin to weaken. Osteomalacia (rickets), which causes bones to soften, and osteoporosis, a disease that weakens the skeleton, are diagnosed and treated by endocrinologists. Menopause, loss of testicle function and aging also can reduce these hormones, putting you at risk for bone fractures.

Patients with diabetes have too much sugar in their blood. The amount of blood sugar must be controlled to prevent serious problems with eyes, kidneys and nerves leading to blindness, dialysis or amputation of limbs.

Endocrinologists work closely with diabetic patients, who control their blood sugar with diet and medications, including insulin.

Pediatric endocrinologists treat children who experience endocrine problems that cause short stature and other growth disorders due to a lack of growth hormone.

Adults with growth hormone deficiency can experience emotional distress and fatigue. Safe and effective growth hormone replacement therapy is available for people whose growth hormone is abnormal.

Hypertension (high blood pressure) is a risk factor for heart disease. Up to 10 percent of people have hypertension because of too much aldosterone, a hormone produced in the adrenal glands. About half of these cases are caused by growths that can be removed with surgery. Conditions such as the metabolic syndrome or a rare adrenal growth called a pheochromocytoma also can cause hypertension. These conditions can be treated successfully.

Lipid Disorders
Patients with lipid disorders have trouble maintaining normal levels of fat in the blood. One of the most common lipid disorders is hyperlipidemia -- high levels of total cholesterol, high levels of low-density lipoprotein (LDL, or "bad" cholesterol) or high levels of triglycerides in the blood. High levels of these fats are linked to heart disease, stroke and peripheral vascular disease (poor circulation in the legs).

Endocrinologists detect factors that might be related to lipid disorders, such as hypothyroidism, drug use (such as steroids), or genetic or metabolic conditions. Lipid disorders involve several conditions requiring special management, including the metabolic syndrome, polycystic ovary syndrome (PCOS) and obesity. Diet, exercise and medications can be prescribed to manage hyperlipidemia and other lipid disorders.

Endocrinologists treat patients who are overweight or obese, sometimes due to metabolic and hormonal problems. Thyroid, adrenal, ovarian and pituitary disorders can cause obesity. Endocrinologists also identify factors linked with obesity, such as insulin resistance and genetic problems.

Pituitary Gland
The pituitary is the master gland of the body because it controls other glands. The pituitary makes several important hormones. Overproduction and underproduction of pituitary hormones can lead to infertility, menstrual disorders, growth disorders (acromegaly, or short stature) and too much cortisol production (Cushing's syndrome). Endocrinologists control these conditions with medications and sometimes refer patients to surgery.

About one in 10 American couples is infertile. Endocrinologists diagnose and treat hormone imbalances that can cause infertility, and assess and treat patients with reproductive problems. They work with patients who need hormone replacement. They also treat menopause symptoms, irregular periods, endometriosis, polycystic ovary syndrome (PCOS), premenstrual syndrome and impotence.

Patients with thyroid disorders often experience problems with their energy levels. They also can have difficulty with muscle strength, emotions, weight control, and tolerating heat or cold. Endocrinologists treat patients with too much or too little thyroid hormone. They help patients reach a hormone balance by replacing or blocking thyroid hormones. Endocrinologists receive special training to manage patients with thyroid growths or cancer, and enlarged thyroid glands.