Steroid Hormones

What are steroid hormones derived from?

cholesterol

Where are steroid hormones synthesized?

adrenal glands and gonads

Where are the receptors steroid hormones bind to located?

located in cytosol (intracellular receptors)

What are the classes of steroid hormones?

mineralocorticoids, glucocorticoids, androgens, estrogens, progestins

What is the function of mineralocorticoids?

involved in electrolyte regulation

What is the function of glucocorticoids?

involved in carb metabolism and immune system regulation

What are androgens?

male sex hormones (ex. testosterone)

What are estrogens?

female sex hormones

What are progestins?

steroid hormones involved in menses regulation and lactation

Which sex produces progestins?

males and females

Draw steroid hormone synthesis

What is cholesterol converted to in steroid hormone synthesis?

progesterone (C21)

How is cholesterol converted to in steroid hormone synthesis?

side chain on cholesterol is cleaved

What enzyme catalyzes cholesterol to progesterone?

cholesterol side chain cleavage enzyme (P450scc)

What is cholesterol side chain cleavage enzyme referred to as?

P450scc

What can progesterone be converted to?

many steroid hormones (mineralocorticoids, glucocorticoids, androgens, estrogens)

What enzyme catalyzes breakdown of progesterone to androgen?

lyase

What enzyme catalyzes breakdown of androgen to estrogen?

aromatase

What enzyme catalyzes breakdown of progesterone to mineralocorticoid?

21 alpha hydroxylase

What enzyme catalyzes breakdown of progesterone to glucocorticoid?

21 alpha hydroxylase

Describe the path of steroid hormones to the cell

transported in blood with carrier proteins

free form diffuses through cell membrane

binds to intracellular hormone receptors

Do all steroid hormones have the same receptor?

no bind to their respective receptors

What occurs when the steroid hormone binds to its HR?

conformational change occurs resulting in dimerization

HR translocates to nucleus and binds to DNA Hormone Response Elements (HRE)

This binding upregulates transcription of associated genes

Define dimerization

formation of dimer

What does HR resemble as it binds to its HRE?

transcription factor

What does HRE resemble when HR binds to it?

enhancer