Presentation on theme: "Local Hormones Prof. K. Sivapalan. 08-01-14Local Hormones.2 Pineal gland Remnant of third eye in lower animals Secrets Melatonin 0.1 – 0.18 g. In infants."— Presentation transcript:
08-01-14Local Hormones.2 Pineal gland Remnant of third eye in lower animals Secrets Melatonin 0.1 – 0.18 g. In infants it is large Begins to involute before puberty. Calcium carbonate and phosphate [pineal sand] accumulates. X’ ray- landmark.
08-01-14Local Hormones.7 Erythropoietin. Glycoprotein with 165 Amino acids. 85% from Kidney and 15% from liver. By interstitial cells in peritubular capillary bed and perivenous hepatocytes. Liver cannot compensate when kidneys are damaged. Hypoxia stimulates secretion. Increases committed stem cell and haemopoisis. Renal disease- normocytic normochromic anaemia.
08-01-14Local Hormones.8 1, 25- dihydroxycholecalciferol Conversion in kidney Regulated by PTH.
08-01-14Local Hormones.9 Renin Mw- 37326,.half life- 80minutes. From Juxta Glomerualar Apparatus, by juxta glomerular cells of afferent arterioles. Action- angeotensinogen to angeotensin I.
08-01-14Local Hormones.10 Regulation of Renin secretion. Stimulation- Increased sympathetic activity. Increased circulating catecholamines. Prostaglandins. Inhibition- Increased Na and Cl absorption across macula densa. Increased afferent arteriolar pressure. Angeotensin II. Vasopressin.
08-01-14Local Hormones.11 Conditions that increase secretion Sodium depletion. Diuresis Hypotension Haemorrhage Upright posture Dehydration Cardiac failure. Cirrhosis Constriction of renal artery Various psychological stimuli.
08-01-14Local Hormones.12 Angeotensinogen 453 amino acids and 13% carbohydrate. Circulating levels increased by- –glucocorticoids. –thyroid hormones –estrogens –several cytokinins Converted to angeotensin I by Renin. Angeotensin converting enzyme in lungs and other endothelial cells converts it into Angeotensin II.
08-01-14Local Hormones.13 Activation of Angeotensinogen.
08-01-14Local Hormones.14 Actions of Angeotensin II Vasoconstriction, more in Efferent arterioles. Stimulates aldosteron secretion. Reduces sensitivity of baro-reflex in CNS. Stimulates thirst centre. Stimulates secretion of vasopressin and ACTH.
08-01-14Local Hormones.15 Endocrine Function of the Heart. Left Atrium Secrets Atrial Natriuretic Peptide. Stimulation is increased NaCl intake and increased ECF volume. Increases Na loss from Kidney- ?increased GFR.
Peptide YY Secreted by L cells of intestine Blood level is proportional to calories in the food Controls appetite Peripheral administration of PYY3-36 inhibits food intake for several hours in both rodents and man May be important in the everyday regulation of food intake 08-01-14Local Hormones.17
Leptin Secreted by adipose tissue in proportion to fat storage Regulates food intake 08-01-14Local Hormones.18
08-01-14Local Hormones.19 Histamine. Found in Mast cells and basophils with heparin. Also found in gastric mucosa. Neurotransmiter.
08-01-14Local Hormones.20 Effects of Histamine. Arteriolar and capillary dilatation. Smooth muscle contraction in Bronchus and GIT. Acid secretion in stomach. Itching and pain. Anaphylaxis.
08-01-14Local Hormones.21 Seerotonin. Found in platelets and GIT and some tissues. Stimulates smooth muscle contraction in, arteriols, bladder, intestine, uterus etc. Nervous system- neurotransmitter..
08-01-14Local Hormones.22 Prostaglandins. Synthesized from Arachidonic Acid. Several varients are found in several tissues. They may be the ultimate mediators of all actions.