Amine, Peptide, Protein, and Steroid Hormone Structure

amine hormones

What are hormones derived from the modification of amino acids referred to as?

carboxyl group is removed

What happens to the -COOH group during amino acid modification for amine hormones?

amine group remains

Which part of the amino acid structure remains unchanged during modification?

tryptophan or tyrosine

Which two amino acids are amine hormones synthesized from?

melatonin

What is an example of a hormone derived from tryptophan?

pineal gland

Which gland secretes melatonin?

regulate circadian rhythm

What does melatonin help with?

tyrosine derivatives

What are thyroid hormones and catecholamines classified as?

metabolism-regulating thyroid hormones

What is one function of tyrosine-derived hormones?

catecholamines

What are epinephrine, norepinephrine, and dopamine collectively called?

adrenal medulla

Where are epinephrine and norepinephrine secreted from?

fight-or-flight response

What role do epinephrine and norepinephrine play?

dopamine

Which catecholamine is secreted by the hypothalamus?

inhibits the release of certain anterior pituitary hormones

What does dopamine do?

peptide and protein hormones

What consists of multiple amino acids that link to form an amino acid chain?

short chains of amino acids

What do peptide hormones consist of?

longer polypeptides

What do protein hormones consist of?

DNA is transcribed into mRNA, which is translated into an amino acid chain

How are peptide and protein hormones synthesized?

antidiuretic hormone (ADH)

What is an example of a peptide hormone important in fluid balance?

atrial-natriuretic peptide

Which peptide hormone is produced by the heart?

decrease blood pressure

What does atrial-natriuretic peptide help with?

growth hormone

What is an example of a protein hormone produced by the pituitary gland?

follicle-stimulating hormone (FSH)

Which protein hormone has an attached carbohydrate group?

glycoprotein

How is FSH classified?

maturation of eggs in the ovaries and sperm in the testes

What does FSH help stimulate?

steroids

What are the primary hormones derived from lipids called?

cholesterol

What lipid are steroid hormones derived from?

testosterone and the estrogens

What are examples of reproductive steroid hormones?

gonads (testes and ovaries)

Where are testosterone and estrogens produced?

aldosterone

Which steroid hormone is involved in osmoregulation?

cortisol

Which steroid hormone plays a role in metabolism?

not soluble in water (they are hydrophobic)

What is a property of steroid hormones?

bound to a transport protein

How must lipid-derived hormones travel to their target cell?

extends the half-life of steroid hormones

What does the complex structure of steroid hormones do?

half-life

What is the time required for half the concentration of the hormone to be degraded called?

60 to 90 minutes

What is the approximate half-life of cortisol?

approximately one minute

What is the approximate half-life of epinephrine?

positive feedback loops

What is characterized by the release of additional hormone in response to an original hormone release?

oxytocin during childbirth

What is a positive feedback loop example?

signals the uterine muscles to contract

What does the initial release of oxytocin do?

pushes the fetus toward the cervix

What does uterine contraction do?

signals the pituitary gland to release more oxytocin

What does cervical stretching cause?

labor contractions to intensify

What does additional oxytocin cause?

decreases after the birth of the child

When does oxytocin release stop?

negative feedback loop

What is the more common method of hormone regulation?

inhibition of further secretion of a hormone

What characterizes negative feedback?

regulated within a narrow range

What does negative feedback allow for hormone blood levels?

glucocorticoid hormones from the adrenal glands

What is a negative feedback example?

hypothalamus and pituitary gland

What directs glucocorticoid release?

glucocorticoid concentrations in the blood rise

When do the hypothalamus/pituitary reduce signaling?

prevent additional glucocorticoid secretion

Why do the hypothalamus and pituitary gland reduce signaling?

stimulated by the release of hormones from the hypothalamus and pituitary gland

What activates adrenal glucocorticoid release?

inhibited when glucocorticoid levels become elevated

When does glucocorticoid signaling stop?

causing negative signals to the pituitary gland and hypothalamus

How do elevated glucocorticoids inhibit further release?