Introduction to hormones & neurotransmitters. Prof K Syed Department of Biochemistry & Microbiology University of Zululand Room no.

Transcription

1 Introduction to hormones & neurotransmitters Prof K Syed Department of Biochemistry & Microbiology University of Zululand Room no. 247

2 Topics Major systems of human body Glands Hormones vs neurotransmitters Classification of hormones Solubility Where they function Chemical structure Briefing on synthesis of hormones/neurotransmitters Physiological role of hormones/neurotransmitters

3 Major system of human body

4 Glands

5 Hormones vs neurotransmitters A hormone is any member of a class of signaling molecules produced by glands in multicellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behavior. Neurotransmitters, also known as chemical messengers, are endogenous chemicals that enable neurotransmission. Nervous System Neurons release neurotransmitters A neurotransmitter acts on specific cell right next to it. Neurotransmitters have their effects within milliseconds. The effects of neurotransmitters are short-lived. Performs short term crisis management Endocrine System Endocrine cells release hormones Hormones travel to another nearby cell or act on cell in another part of the body. Hormones take minutes or days to have their effects. The effects of hormones can last hours, days, or years. Regulates long term ongoing metabolic function

6 Classification Hormones Solubility Where they function Chemical structure Fat soluble hormones Water soluble hormones Endocrine hormones Autocrine hormones Paracrine hormones Proteins/polypeptides hormones Steroid hormones Amino acid derivative hormones

7 Hormones classification Hormones classification based on chemical structure Proteins/polypeptides hormones Amino acids ( 3) Rough endoplasmic reticulum Water soluble as they are charged Can not cross the membrane Receptors in/on cell surface Receptor mediated signaling Steroids hormones Lipids (cholesterol) Cross the cell membrane Receptors inside the cell (cytoplasm or nucleus) Affect transcription or translation One amino acid Derivatives Dual signaling mode Amino acid derivatives Insulin Glucagon Progestagens Progesterone Glucocorticoids Cortisol Mineralocorticoids Aldosterone Estrogens Estrone Androgens Testosterone Tyrosine derivatives Histidine derivatives Tryptophan derivatives Thyroid hormones Catecholamine hormones Histamine Serotonin Thyroxine Dopamine Norepinephrine Epinephrine

8 Insulin & Glucagon

9 Steroid hormones

10 Amino acid derivatives: Thyroid hormones Triiodothyronine (T3) 20% Tetraiodothyronine (T4) 80%

11 Amino acid derivatives: Catecholamine

12 Amino acid derivatives: Histamine & Serotonin Histamine is derived from the decarboxylation of the amino acid histidine, a reaction catalyzed by the enzyme L-histidine decarboxylase

13 Hormones functions Hormones Insulin Glucagon Cortisol Aldosterone Major functions (i) Primary regulator of blood glucose concentration (ii) Promotes glucose uptake in muscles and adipose tissue (iii) Inhibit hepatic glucose production and promotes glycogen synthesis and lipogenesis (iv) Stimulates cell growth and differentiation by increasing the synthesis of glycogen, proteins and triacylglycerol (i) Helps make glucose available to other tissues when the concentration of circulating glucose drops (ii) Promotes glycogenolysis and inhibit glycogen synthesis in liver (iii) Promotes lipolysis in adipose tissue (i) Promote gluconeogenesis and the formation of glycogen (ii) Enhances the degradation of fat and protein (iii) Inhibit the inflammatory response (iv) Enable animals to respond to stress (i) Regulate the excretion of salt and water by the kidneys (ii) Act on the distal tubules of the kidney to increase the reabsorption of Na + and the excretion of K + and H + (iii) increases blood volume and blood pressure

14 Hormones functions Hormone Major functions Testosterone (i) Development of male reproductive tissues such as testis and prostate (ii)promotes secondary sexual characteristics such as increased muscle and bone mass, and the growth of the body hair (iii)prevents osteoporosis Beta-Estradiol (estrogen) Thyroxine (i) Development and regulation of the female reproductive systems (ii) Promote the female secondary sex characteristics, such as breasts (iii) Regulate menstrual cycle (i) Essential hormone in the body (ii) Control basic metabolic rate and energy production (iii) Controls cardiovascular system, central nervous system and reproductive system (iv) Controls growth and development system and digestive system (v) Enhances hydration of skin and growth of hair

15 Hormones functions Neurotransmitters Dopamine Major known functions Critical for memory and motor skills. Deficiency in dopamine production is associated with Parkinson s disease, a degenerative condition causing shaking palsy Norepinephrine (also a hormone) Epinephrine Histamine Serotonin Neuromodulator optimizes brain function. As part of bodies fight or flight hormone norepinephrine quickly provides an accurate assessment of danger or stressful situations. Activates muscle adenylate cyclase, thereby stimulates glycogen breakdown. Promotes lipolysis in adipose tissue. Promotes Glycogenolysis and Gluconeogenesis in Liver. Involved in allergic responses as well as in the control of acid secretion by the stomach It is popularly through to be a contributor to feelings of well-being and happiness. Important factor in mood, depression, anxiety, sleep quality, emotions and regulation of appetite and body temperature. However, biological functional role of serotonin is not clear.

16 Sources Berg, JM, Tymoczko JL and Stryer, L. Biochemistry, sixth edition, W.H. Freeman and Company, New York, Voet, D, Voet, JG and Pratt CW. Principles of biochemistry, third edition, John Wiley & Sons, Inc, Hormones - What are hormones - Functions of hormones - Types of hormones. Types of hormones/overview of cell signaling: Types of hormones Endocrine system physiology NCLEX-RN Khan Academy Insulin and glucagon Chemical processes MCAT Khan Academy. What does cortisol do to the body? Aldosterone raises blood pressure and lowers potassium NCLEX-RN Khan Academy. Aldosterone functions. Testosterone Reproductive system physiology NCLEX-RN Khan Academy. Estrogen Reproductive system physiology NCLEX-RN Khan Academy. Functions of thyroxine. Neurotransmitters and their functions. 2-Minute neuroscience: Dopamine. 2-Minute neuroscience: Serotonin. Excellent information on neurotransmitters: Excellent information on hormones vs neurotransmitters: