L1: Principles of Endocrinology

Question 1

Exocrine vs. Endocrine vs. Paracrine?

Answer 1

Question 2

Peptide Hormones characteristics?

Answer 2

• Hydrophilic/water soluble
• Synthesized on rough ER
• Stored in secretory vesicles

Question 3

Amine Hormones and their Characteristics?

Answer 3

All derived from amino acid tyrosine (tyr)

Catecholamines (Epinephrine/Norepinephrine)

• Stored in cellular vesicles (Chromaffin Granules)
• Small hydrophilic/water soluble
• Short Plasma half-life (10-100 sec)

Thyroid Hormones (T4 (Thyroxine), T3)

• Stored in large extracellular deposits
• Non-polar can diffuse across plasma membrane => target cell receptors are intracellular
• Requires plasma transport proteins to reach target cells

Question 4

Steroid Hormones and their Characteristics?

Answer 4

All derived from cholesterol

Adrenal Cortex

• Cortisol - Glucocorticoid
• Aldosterone - Mineralocorticoid

Gonads/Placenta

• Testosterone - Androgen
• Estradiol - Estrogen
• Progesterone - Progestin

Storage/Synthesis

• Synthesized by enzymes located in mitochondria / smooth ER
• Not stored but released immediately from cell after synthesis
• Extremely hydrophobic/not soluble in water

§ can freely diffuse across plasma membrane at sites of synthesis and action

§ require plasma transport proteins to reach target cell

§ intracellular receptors in target cells

• Are slower acting and have longer half-life than peptide hormones

Question 5

Hormones that use a cAMP Secondary Messenger?

Answer 5

Vasopressin (ADH)

FSH/TSH

Somatostatin

Oxytocin

Glucagon

Calcitonin

Question 6

Hormones that use a Ca /Calmodulin Secondary Messenger?

Answer 6

Catecholamines - epinephrine/norepinephrine

TRH

ADH

Luteinizing Hormone-Releasing Hormone (LHRH)

Oxytocin

Question 7

Hormones that use a Receptor Associated (JAC-STAT) Tyrosine Kinase?

Answer 7

Growth Hormone

Prolactin

Question 8

Hormones that use Integral Tyrosine Kinases?

Answer 8

Insulin

IGF-1/2

Question 9

What is the Ferguson Reflex?

Answer 9