PGY452 552 Endocrine physiology 4 Complex inputs and the central nervous system A B C CNS endocrine anatomy Posterior pituitary Anterior pituitary 1 2 3 D E Hypothalamic inputs Hormones Feedback Endocrine disease You now know everything Types of input Simple inputs Sensed by endocrine tissue directly Response regulates input Always negative feedback Examples Hormone H H H H H H Simple Input Glucose H H Complex CNS integrated regulation of complex stimuli Feedback can be H H Ca ECF H Response Negative Positive 2 The 4th path to target response neuroendocrine H Specialized nerve cells Many peptide hormones are neurotransmitters Can go both ways H H signal H Response H 3 Most neuronal control occurs through the hypothalamus and the pituitary gland Diencephalon Corpus callosum Thalamus Hypothalamus Pineal gland Pituitary gland 4 The pituitary is really two glands Anterior front Posterior back Anterior pituitary a true gland of epithelial origin Infindibulum Anterior pituitary hypothalamus Hypothalamicpituitary axis HPA Hypothalamu s Sphenoid bone Posterior pituitary an extension of hypothalamic neural tissue 5 Anterior posterior pituitaries do NOT share circulation Do not interact directly 6 The posterior pituitary Two 9 amino acid peptide hormones Antidiuretic hormone ADH Vasopressin Oxytocin Prohormones travel down long axons Processed to mature hormones Released into capillary beds Hypothalamus Prohormones made in large neural soma Blood flow in To general circulation 7 The anterior pituitary Hypothalamic regulating hormones made in small neural soma Blood flow in Regulate trophic hormone synthesis and release from specific endocrine epithelial cells Small compared to posterior pituitary neurons Regulating hormones released into portal circulation Travel down capillary beds Trophic hormones to general circulation 8 HPA allows endocrine system to respond to complex stimuli Complex inputs Sleep wake Pain Senses Energy in out Hypothalamic integrating center Six hypothalamic regulatory hormones Emotions Temperature Six anterior pituitary tropic hormones Water balance Autonomic inputs Regulate Metabolism Stress response Development 9 Somatostatin GHIH PIH dopamine GnRH CRH Adrenal cortex FSH LH Prolactin TSH GHRH GH Anterior Pituitary ACTH TRH Hypothalamus Hormones of the hypothalamic anterior pituitary axis Thyroid gland Gonads Breast Cortisol Aldosterone Thyroid hormone Androgens estrogens Many tissues IGF 1 10 Anterior pituitary secretes hormones from specialized cell types Proportion of each cell type This is where the idea of a master gland comes from Mammotroph Growth hormone Thyroid Stimulating H Corticotroph Somatotroph Luteinizing H Follicle Stimulating H Adrenocorticotropin Prolactin Gonadotroph Thyrotroph 11 Anterior pituitary control loops Hypothalamus RH Long loop negative feedback H hormone T tropic R releasing Ultra short loop negative feedback Short loop negative feedback Input Anterior pituitary TH Peripheral endocrine tissue H All hormones regulated by feedback THIS TERMINOLOGY APPLIES ONLY TO THE HPA Also Long and short loop positive feedback Ultrashort loops within the anterior pituitary or hypothalamus Short long loop negative feedback the most common HOMEOSTASIS 12 HPA feedback is key to endocrine disease Receptor Tissue fails to respond Hormone deficiency hyposecretion Destruction of the gland Infection Infarction Autoimmune attack Genetic defects in hormone production Protein hormone gene mutation Mutations in any protein involved in steroid or protein hormone synthesis Excess hormone hypersecretion Tumors not subject to feedback or other regulation Gland Ectopic due to dedifferentiation of non endocrine tissue Abuse Overconsumption of prescribed or abused Hormone Hormone receptor agonist 13 Primary vs secondary endocrine disease in the HPA Excess peripheral hormone causes the symptoms Secondary disease Primary disease H TH RH H TH RH Hypothalamus Hypothalamus Tumor RH Tumor RH Anterior pituitary Anterior pituitary TH TH Peripheral endocrine tissue Peripheral endocrine tissue H H 14 Note that Releasing hormones or inhibiting hormones are always secreted by the hypothalamus Releasing hormones mostly G q Inhibiting hormones G i GHRH vs GHIH G s vs G i Anterior pituitary hormones are usually given some sort of regulatory designation Thyroxine stimulating hormone Adrenocorticotrophic hormone Follicle stimulating hormone Hypothalamus all peptides except dopamine PIH Anterior pituitary all glycoproteins peptides No steroid hormones are made in the hypothalamus or pituitary 15 Remember this We will cover 40 hormones 70 recognized hormones 100 s meet the technical definition 16 You now know EVERYTHING about them Don t panic BUT you do need to get to work It is important that you grasp these topics soon The rest of the time will be spent o Covering hormone function o Unique responses Compare contrast steroid protein hormone properties 17 Review questions 1 Identify which of the following hormones are proteins or steroids and if their origin is from the anterior pituitary the hypothalamus or neither Hormone Androstenedione Follicle stimulating hormone Growth hormone inhibiting hormone Thyroid stimulating hormone Insulin Cortisol Corticotropin releasing hormone Type Endocrine tissue 2 Draw and label a hypothalamus with a posterior and anterior pituitary Add a short and long feedback loop 3 A hormone is released from the posterior pituitary and inhibits the release of something releasing hormone Would this be considered long loop short loop or ultrashort loop negative feedback 4 Define the following a Portal Circulation b The suffixes tropic or trophic statin and medin 18 Notes SLIDE 5 This is about the time when someone who took anatomy informs me that they learned the terms adenohypophysis for anterior pituitary and neurohypophysis for posterior pituitary That s precious but I don t care Nobody has used these terms in the endocrine literature for at least 30 years you don t see them in physiology endocrine or even medical text books and besides they are hard to pronounce You should know the meanings of anterior posterior and the HPA SLIDE 7 The Portal Circulation is a part of the circulatory system where a vein drains into a capillary bed then back into the venous system as opposed to normal circulation where the blood goes from arterial capillary venous circulation It is unusual and yes the best known example is in the liver SLIDE 10 A tropic or trophic hormone is one