1. Endocrine system
consists of endocrine glands, that secret chemical substance (hormone) regulating physiological responses. The endocrine system and nervous system are two major communication systems that control homeostasis of the body.

2. Hormone
derived from Greek hormaein meaning "to excite" and was coined by Bayliss and Starling to denote the concept of a diffusible physiological regulator. They discovered secretin, a 29 amino acid peptide, which is released by secretory S cells of the duodenum of the gastrointestinal system in response to H+.

3. Properties of hormones
secreted by specialised glands
carried by blood stream (ductless)
acting in remote target
trace amount causes tremendous effects
binding to specific receptors
usually has short half life and tightly regulated

4. Chemical classification of hormones:
Amine hormones:derivatives of tyrosine; epinephrine, norepinepherine, thyroid hormone, dopamine
Polypeptides and glycoproteins: transcribed from truncated genes; GnRH, GH, insulin, etc..(the largest group)

5. Steroids metabolites of cholesterol
 glucocorticoid (cortisol): mineralcorticoid (aldosterone):
 progestin (progestone):
 androgens (testosterone):
 estrogens (17b-estradiol):
 cholecalciferol (1, 25-dihydroxyvitamin D3).

6. Adrenal Cortex
Five hormones are secreted by adrenal gland: Aldosterone, cortisol, corticosterone, dehydroepiandrosterone (DHEA), and androstenedione
DHEA and androstenedione are known as androgens, action similar to male hormone, testosterone, but weaker

7. Gonadal hormones

8. Fatty acid derivatives
Prostaglandins, leukotrienes, hydroxyeicosatetranenoic acid (HETE).
Known in 1930s, Euler and Goldblatt identified substance that causes blood vessel and smooth muscle contraction from semen. (prostaglandin)

9. Physiological effects of prostaglandins:
inflammation:
Reproduction:
Respiration:
renal function:
blood vessel:
gastrointestine

10. Mode of hormone secretion
Hormone release into the blood is infrequently monotone but rather is a complex phenomenon as reflected in rapid changes of plasma concentration at more or less regular intervals named pulsatile release
Pulse:
Frequency:
Amplitude

11. Hormone transport and metabolism
steroid and thyroid hormones
Binding to specific proteins
Nuclear or cytosolic receptor
Slow (hours to days) metabolism
Other hormones
Free in blood stream
Membrane receptor
Fast (minutes to hour) metabolism

12. Fate and actions of a hormone

13. Mechanisms of hormone action
Receptor concept: Only cells express specific “receptor” can response to a particular hormone
Nuclear receptor: steroid and thyroid hormones
Plasma membrane receptor: other hormones
Effect of hormone-receptor binding (Table 11-2)

14. Actions of hormones with membrane receptor
Hormonal signal transduction pathways:
cAMP/PKA
Phospholipase C (PLC)
Receptor tyrosine kinase
JAK-STAT:
Ion channel

15. Permissive effect
A hormone increases another hormone’s effectiveness: mainly by upregulating the receptor of the second hormone

16. Inputs that control hormone secretion
Can be regulated by more than one input.
Change in the plasma concentrations of mineral ions or organic ions
Neurotransmitters released from neuron
Another hormone or neurohormone

17. Control by plasma mineral ions or organic nutrients
Examples:
Insulin: controlled by plasma glucose concentration
Parathyroid hormone (PTH): controlled by plasma [Ca+2]

18. Control by Neurons Adrenal medulla: by autonomic nervous system
Hypothalamus: by other neurons

19. Types of Endocrine Disorders
Hyposecretion: too little hormone
Primary hyposecretion: adrenalectomy; Lack of dietary iodine leading to low thyroid hormone
Secondary hyposecretion: lack of tropic hormone
Hypersecretion: too much hormone
Primary
Secondary
Hypo- and Hyper responsiveness: abnormal of receptors, abnormal of signal transduction pathway, abnormal in metabolic activation

22. Synthesis of Peptide Hormones

24. Steroids

25. Synthesis of Steroid Hormones

27. Typical profile of hormones