Lecture 1 - Endocrinology Pt 1(Ch 5 Definitions –...

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Unformatted text preview: Endocrinology - Pt. 1 (Ch. 5) Definitions – Endocrinology – Endocrine Gland – Hormone Endocrinology - Pt. 1 (Ch. 5) Definitions – Endocrinology – the study of secretions by endocrine glands and their related disorders Endocrine System Function wireless communication system connects the body parts Circulatory System Endocrinology - Pt. 1 (Ch. 5) Definitions – Endocrinology – the study of secretions by endocrine glands and their related disorders – Endocrine Gland – ductless gland secreting a substance into the blood or lymph which acts on a target tissue Endocrine Glands Endocrine Hypothalamus Pituitary Pineal Adrenal Ovary Uterus Placenta Testes (in males) Thyroid Pancreas Endocrinology - Pt. 1 (Ch. 5) Definitions – Endocrinology – the study of secretions by endocrine glands and their related disorders – Endocrine Gland – ductless gland secreting a substance into the blood or lymph which acts on a target tissue – Hormone – Hormones Hormones Hormones can be used to regulate body functions – Growth – Lactation – Estrous Cycles – Parturition – Super Ovulation – Birth Control Name a few hormones? Name metabolic hormone ­ critical for life – – – Hint ­ increases after a meal Hint ­ absence requires 1­2x/day inj. Hint ­ regulates glucose Name a few hormones? Name reproductive hormone ­ steroid – – – Hint ­ associated with increased aggressiveness, sexual interest Hint ­ present in males and females Hint ­ administered exogenously causes infertility in men Name a few hormones? Name reproductive hormone ­ steroid – – – Hint ­ causes ‘heat’ or estrous behavior Hint ­ present in males and females Hint ­ in women, helps prevent osteoporosis Hormone Hormone Concentrations required for action – – – ug, ng, pg micro, nano, pico 10­6, 10­9, 10­12 grams How do we measure? – – – Bioassay Radioimmunoassay (RIA) Elisa How do we study hormones? How Ablation Replacement Isolate hormone Assay Changes in Hormone Levels How do we study hormones? How Ablation Replacement Isolate hormone Assay Changes in Hormone Levels Types of Secretion Types Endocrine Exocrine Paracrine Autocrine Types of Secretion Types Endocrine – secreted into blood (or other fluid) to target tissue Most hormones Endocrine Endocrine Classical effects of hormones -substance produced in one site travels via blood supply to affect processes in another organ (tissue) Endocrine Endocrine a LH from Anterior Pituitary a LH from Anterior Pituitary b Travels via blood­ stream to testes Endocrine Endocrine a LH from Anterior Pit. b c increase in testosterone Travels via blood­ stream to testes Endocrine Endocrine How do we make practical use of endocrine effects of hormones? Types of Secretion Types Endocrine – secreted into blood (or other fluid) to target tissue Most hormones Exocrine ­ secreted to a surface, lumen or a duct Paracrine – secreted by a cell, acting on saliva , sweat, pancreatic enzymes an adjacent cell Paracrine Paracrine hormone from one cell alters activities (+/-) of a ‘neighbor’ cell Paracrine Paracrine growth factor Types of Secretion Types Endocrine – secreted into blood (or other fluid) to target tissue Most hormones Exocrine ­ secreted to a surface, lumen or a duct Paracrine – secreted by a cell, acting on saliva , sweat, pancreatic enzymes an adjacent cell Autocrine – secreted by a cell, acts back on same cell Autocrine Autocrine hormone from one cell alters activities (+/-) of the same cell Autocrine Autocrine growth factor Paracrine and Autocrine Paracrine How do we make practical use of these effects of hormones? Classifying Hormones Classifying Site of Production Type of Action Chemical Structure – Reproduction – Metabolic – General (protein, steroid…..) – Size Classifying Hormones Classifying Site of Production Type of Action Chemical Structure – Reproduction – Metabolic – General (protein, steroid…..) – Size Hormones of the Hypothalamus and Pituitary Hypothalamus Anatomy – – hypothalamus pituitary physical blood supply Connections – – Hypothalamus & Pituitary Hypothalamus Third Ventricle Hypothalamus Optic Chiasm Mammilary Body Pituitary Functions of the Hypothalamus Functions translator : sensory ­­­ hormonal axons & capillary beds (plexus) pulse generator neurosecretory cells & neurohormones Hypothalamic Hormones Hypothalamic Gonadotropin­releasing hormone (GnRH) Corticotropin releasing hormone (CRH) Growth Hormone Releasing Hormone Thyrotropin Releasing Hormone Opioid Peptides Pituitary Pituitary Located above the roof of the mouth, below the hypothalamus Consists of 2 parts – Anterior – glandular tissue – Posterior – neural tissue Anterior Pituitary No direct connection to hypothalamus Blood supply M.E. derived from hypophyseal portal system ­ Anterior Drains from median eminence of hypothalamus Hypothalamus Nerve Cells Capillary plexus Pituitary Posterior pituitary Example: Pulse Generator Releasing Hormones from Hypothalamus – Released in pulses Stimulate anterior pit. Hormones – Released in pulses Hypothalamus Nerve Cells GnRH Anterior Pituitary Capillary plexus Posterior pituitary LH Anterior Pituitary Hormones Anterior luteinizing hormone (LH) follicle stimulating hormone (FSH) prolactin (PRL) thyroid stimulating hormone (TSH) somatotropin (ST, GH) adrenocorticotropic hormone (ACTH) Posterior Pituitary Direct connection to hypothalamus via infundibular stalk – neural tissue Direct extension of axons of Anterior hypothalamus Pituitary Hormone STORAGE not SYNTHESIS Hypothalamus Nerve Cells Infundibular Stalk Capillary plexus Posterior pituitary Example: Hypothalamus Oxytocin produced by hypothalamus – Stored in Posterior Pituitary Released into blood stream Nerve Cells Anterior Pituitary Oxytocin Posterior pituitary Oxytocin Posterior Pituitary Hormones Posterior Oxytocin Anti­Diuretic Hormone (ADH) or Vasopressin Gonadal Hormones Gonadal progesterone testosterone estradiol relaxin inhibin androstenedione oxytocin Classifying Hormones Classifying Site of Production Type of Action Chemical Structure – Reproduction – Metabolic – General (protein, steroid…..) – Size Type of Action Type Reproduction: Metabolic: – Hypothal: GnRH, GHRH – Ant. Pit.: LH, FSH, PRL, GH – Post. Pit: OT – Hypothal: CRH, TRH – Ant. Pit.: ACTH – Post. Pit: ADH Classifying Hormones Classifying Site of Production Type of Action Chemical Structure – Reproduction – Metabolic – General (protein, steroid…..) – Size Chemical Structure Chemical Proteins Peptides Steroids – Long chains of amino acids – Short chains of amino acids – Cholesterol and fatty acids – Derived from arachidonic acid – 1 amino acid Prostaglandins Biogenic Amines and Catecholamines Chemical Structure Chemical Peptide GnRH Oxytocin Protein LH FSH Prolactin Relaxin Inhibin GH Steroid Estrogen Androgen Progesterone Prostaglandins PGF2α Amines Melatonin FSH, LH, TSH (& hCG) FSH, two subunits – – alpha (Α) beta (Β) A + Β LH = LH A + Β TSH = TSH A + Β FSH = FSH A + Β hCG = hCG beta provides specificity hCG ­ from implanting embryo has similar structure A Α Α FSH + LH TSH Β LH LH FSH TSH Β TSH + + Β FSH Protein Synthesis - Sites Protein DNA mRNA Prohormone mRNA Prohormone Hormone Nucleus RER SER, Golgi Protein Synthesis Protein DNA mRNA Protein Synthesis Protein Prohormone DNA Hormone mRNA Regulation of Hormones Regulation Feedback Mechanisms Changes in hormone levels during the estrous cycle Hormone signaling mechanisms Regulation of Secretion Regulation “up and down“ regulation – – negative feedback positive feedback Negative Feedback Negative Secretion of one hormone decreases secretion of a 2nd hormone LH from pituitary testosterone from testes Negative Feedback Negative (--) LH from pituitary testosterone from testes Secretion of one hormone causes the secretion of a 2nd hormone to increase Unstable system few examples Positive Feedback Positive LH estrogen from ovary (+) LH ‘surge’ estrogen from developing follicles Hormonal Changes During the Estrous Cycle LH P E Days of the estrous cycle Hormonal Changes During the Estrous Cycle LH P High P4 suppress LH E2 suppresses LH secretion (negative) E Days of the estrous cycle Progesterone and LH Progesterone Progesterone exhibits a negative feedback effect on LH levels Progesterone also facilitates estradiol’s negative feedback effect on LH Hormonal Changes During the Estrous Cycle LH P4 decreases P E2 increases and stimulates LH secretion (positive) E Days of the estrous cycle Hormonal Changes During the Estrous Cycle LH P High P4 Suppresses LH secretion (negative) P4 decreases E2 increases and stimulates LH secretion (positive) E Days of the estrous cycle Actions of Hormones Actions mechanism of action – – must bind receptor location of receptors cell membrane (proteins) – think of hormones as inter­cellular signals second messenger or intra­cellular signals nucleus (primarily steroids) Hormone Action - Proteins (Senger Fig. 5-13, 5-14) hormone cell membrane receptor cytoplasm ATP ATP cAMP ATP cAMP Cellular Effects Steroid Hormone Action Steroid (Senger Fig. 5-15) cell nucleus steroid hormone receptor DNA gene expression progesterone receptor DNA gene expression effects?? Example of an Antagonist progesterone RU-486 DNA receptor no action result?? Brief Review of Selected Hormones and their Functions Hormones GnRH LH FSH Estradiol Progesterone Testosterone PGF2a Oxytocin GH (ST) ...
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This note was uploaded on 08/24/2010 for the course ANS 220 taught by Professor Stewert during the Spring '10 term at North Alabama.

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