Biochemistry of Hormones

Hormone Regulation

Hypothalamus- Regulation starts here. Located near the brain stem, it controls the pituitary.

Pituitary- controls the hormone producing areas within the body by sending “communication” hormones.

Examples of Hormones

Adrenaline or epinephrine

produced in the Adrenal Cortex, adjacent to the kidneys

derived from the amino acid tyrosine

Role in body responsible for the fight or flight response characterized by goose bumps, increased heart rate/output and blood pressure. Affects rate of glucose release into the liver and release of glucose by liver into the blood.

Thyroxin; an iodine containing amino acid

Produced in thyroid glands

Derived from small molecule from amino acids

Role in body responsible for basal metabolic rate in vertebrates: essential for regulating metabolism

Insulin; a protein of 51 amino acids

Produced in Pancreas (β –cells islets of Langerhans. These are endocrine cells)

Derived from protein

Role in bodyDecreases blood glucose level; increases glucose and amino acid uptake and use by cells.

Insulin is a globular protein

Sex Hormones: Estrogen and Testosterone

Produced in testes and ovaries

Derived from cholesterol

Role in bodyResponsible for development of secondary sexual characteristics

Negative Feedback System

Regulates the amount of hormone the body producesTarget cells, cells which receive a particular hormone, when receiving a high level of the hormone send a signal to the pituitary Pituitary sends a communication hormone to the production cells to turn off hormone’s production.

A closer look at three hormones: Insulin

Too high a glucose levelTriggers the hypothalamus to release a hormone to the pituitary gland

Pituitary gland releases another hormone (thyroxin) to the pancreas to initiate insulin production.

Insulin cont.

The insulin produced is released into the blood

Attaches to glucose and takes it to cells which need it for metabolism (cellular respiration) and carries any excess glucose to the liver and muscles, where it is either converted into glycogen or converted into fat (stored in adipose tissue).

Cortisol functions in the body

Cortisol is an important hormone in the body, secreted by the adrenal glands and involved in the following functions and more:

Proper glucose metabolism

Regulation of blood pressure

Insulin release for blood sugar maintanence

A quick burst of energy for survival reasons

Cortisol Functions continued

Normally, it’s present in the body at higher levels in the morning, and at its lowest at night. Although stress isn’t the only reason that cortisol is secreted into the bloodstream, it has been termed “the stress hormone” because it’s also secreted in higher levels during the body’s ‘fight or flight’ response to stress, and is responsible for several stress-related changes in the body.

Cortisol functions continued

A quick burst of energy for survival reasons

Heightened memory functions

A burst of increased immunity

Lower sensitivity to pain

Helps maintain homeostasis in the body

Problems with a prolonged release of high doses of cortisol such as with Chronic Stress

Impaired cognitive performanceSuppressed thyroid functionBlood sugar imbalances such as hyperglycemiaDecreased bone densityDecrease in muscle tissueHigher blood pressure Lowered immunity and inflammatory responses in the body, slowed wound healing, and other health consequencesIncreased abdominal fat, which is associated with a greater amount of health problems than fat deposited in other areas of the body.

Cortisol- Produced by adrenal glands

Sexual reproductive hormones

These hormones are: testosterone, adrosterone, estrogen, and progesterone.

They are all cholesterol derivatives.

Both male and female produce all of the hormones but in differing amounts.

Testosterone and androsterone

Most dominant sexual hormones in males.

Produced in the testicles.

Develop secondary male characteristics such as facial hair, deep voice and prominent muscle development.

Testosterone

Estrogen and Progesterone

Most dominant sexual hormones in females.Estrogen:encourages secondary females characteristics such as breast development and wider hips, stimulates ovulation, regulates the absorption of calcium through the diet, maintains flexibility of muscles, skin, and ligaments and tendons.Progesterone: Maintains and develops the reproductive system, prepares the uterus for the embryo, maintain the endometrium lining during pregnancy. (levels are high in pregancy)

Estrogen (Left), Progesterone

Continued.

Birth control pills: contain synthetic progesterone to stop ovulation in women, and estrogen to maintain a regular menstrual cycle. The progesterone stops ovulation by inhibiting the production of LHRH hormone by the hypothalamus, and FSH (follicle stimulating hormone) by the pituitary.

how birth control pills work

Derivatives of Cholesterol: estrogen (top right), testosterone (bottom right)

Abuse of Steriods

Increasing the use of testosterone and other androgen hormones in order to promote muscle mass have harmful side effects>Side effects in men: impotence, small testes, problems urinating, baldness.Side effects in women: some development of male characteristics such as deepened voice, less body fat, more facial hair, reduced breasts. In both sexes: violent tempers, high blood pressure, and heart attacks. Injecting steriods is more effective than taking them orally, because the steriods can break down before reaching the receptor (target) site.

Vitamins2 categories

Water soluble and Fat soluble