endocrinology(内分总论)

1、wang xinjun（王新军）（王新军）department of endocrinology hainan medical collegemp:efinitions and scope of endocrinology classical endocrinology（经典内分泌学）（经典内分泌学） is the study of endocrine glands which are a group of glands in the body secreting hormones to evoke a specific response in other cells

2、 of the body. classical endocrine glands pineal（松果体）（松果体） pituitary （垂体）（垂体） thyroid （甲状腺）（甲状腺） parathyroid （甲状旁腺）（甲状旁腺） adrenal （肾上腺）（肾上腺） islets （胰岛）（胰岛） gonads （性腺）（性腺） endocrineendo-crineendo-a combining form meaning “within,” used in the formation of compound words: endocardial; endocrinologycr

3、ine: paracrine autocrine exocrine endocrinology with development, the definition and scope of investigative and clinical endocrinology continues to expand. for example: heart, kidney, adipose tissue components of the endocrine and metabolic systemsarchitectural and functional properties of endocrine

4、 and metabolic systemendocrine systemendocrine system consists of two main parts: endocrine glands sporadic endocrine tissues and cells in non-endocrine organhypothalamus-pituitary-target glandhypothalamus-pituitaryanterior pituitary releases six hormones: acth、tsh、fsh、lh、prl、ghposterior pituitary r

5、eleases two hormones that are actually produced in the hypothalamus:1. antidiuretic hormone (adh) acts on the kidneys to conserve water and also promotes constriction of blood vessels.2. oxytocin stimulates uterine contractions and promotes milk “letdown” in the breasts during lactation. hormonetarg

6、et functionthyroid (tsh) stimulating thyroid glandth synthesis &releasegrowth (gh)many tissuesgrowthadrenocortico-tropin (acth)adrenal cortexcortisol release(androgens)prolactin (prl)breastmilk productionfollicle (fsh)gonadsegg/sperm prod.luteinizing (lh)gonadssex hormones an excess of growth ho

7、rmone in children causes giantism. in adults it causes acromegaly. dwarfism (lack of growth hormone). excess acth overstimulates the adrenal cortex, resulting in cushing disease. increased prolactin causes milk secretion, or galactorrhea, in both males and females. a specific lack of adh from the po

8、sterior pituitary results in diabetes insipidus(polyuria and polydipsia).hormones pituitarypituitary tsh，acth， gh，prl，lh，fsh peripheral glandperipheral gland thyroidthyroid：t3，t4 parathyroidparathyroid：pth adrenaladrenal：cortisolcortisol、aldosteronealdosterone gonadsgonads：t，dht，e ， p liverliver：igf

9、 kidneykidney：1，25(oh)2d3 isletsislets：insulin, glucagoninsulin, glucagon（胰高血糖素）（胰高血糖素） apart from these glands, there are many tissues and cells sparsely distributed in non-endocrine organs, such as the atrium of the heart, the liver, the kidney, the gastrointestinal tract and the adipose tissues.c

10、lassification of hormonehormones are customarily divided into three groups: proteins and peptides: insulin （蛋白质和肽类激素）（蛋白质和肽类激素） steroids: cortisol （类固醇激素）（类固醇激素） amino acid analogues: t3, t4 （氨基酸类激素）（氨基酸类激素）steroids tissues which produce steroid hormones include ovary/testis, adrenal cortex, placent

11、a and skin(vitamin d). all steroid hormones are based on the precursor molecule cholesterol.regulation of hormone levels spontaneous, or basal, hormone release feedback inhibition by hormones of their synthesis and/or release stimulation or inhibition of hormone release by substances that may or may

12、 not be regulated by the same hormones establishment of circadian rhythms for hormone release by systems such as the brain brain mediated stimulation or inhibition of hormone release in response to anxiety anticipation of a specific activity, or other sensory inputs.hypothalamus-pituitary-adrenal ax

13、is the hypothalamus produces crh, which travels down the portal vessels through the hypothalamic stalk to the anterior pituitary, where it stimulates acth release. acth then travels to the adrenal gland, where it stimulates the release of cortisol. cortisol in turn inhibits both crh and acth release

14、（feedback inhibition）. the brain establishes circadian rhythms and can trigger increased crh release in response to stress.mechanisms of hormone action peptide and catecholamine hormones and prostaglandins bind to receptors on the cell surface. steroid and thyroid hormones act for the most part by b

15、inding to intracellular receptors. binding to receptors on the cell surface binding to intracellular receptorshormones bind to receptors on the cell surface peptide and catecholamine hormones and prostaglandins bind to receptors on the cell surface, where the hormone-receptor interactions affect int

16、racellular mediators, or second messengers.second messengershormones bind to receptors on the cell surfacebinding to intracellular receptorsintracellular receptorsdisorders of the endocrine disorders of the endocrine and metabolic systemand metabolic system most recognizable disorders of the endocri

17、ne system are due to an excess or a deficiency of particular hormones, whether caused by abnormalities of endocrine glands, ectopic production of hormones, abnormal conversion of prohormones to their active forms, or iatrogenic factors.hypofunction of endocrine glands endocrine glands may be injured

18、 or destroyed by neoplasia, infections, hemorrhage, autoimmune disorders, and other causes.hormone deficiency secondary to extraglandular disorders impaired conversion of a prohormone to a hormone occurs in chronic renal failure, in which there is defective conversion of 25-hydroxycholecalciferol to

19、 1,25-dihydroxycholecalciferol.hyporesponsiveness to hormones hormone levels may be normal or even elevated in the presence of manifestations of endocrine deficiency.hormone exess syndromehyperfuction of endocrine glands the most common cause of hormone excess syndromes is hyperfunction of endocrine

20、 glands secondary to tumors of the glands or hyperplasia of several causes.metabolic disorders diabetes mellitus hypoglycemia hyperuricemia and gout disorders of lipid metabolism nutritional/vitamin deficienciessymptoms and signs of endocrine and metabolic diseases hormones affect the function of al

21、l tissues and organ systems. consequently, the symptoms and signs of endocrine disease are extremely diverse. they may vary from generalized, such as fatigue, to localized, such as weakness of the extraocular muscles.generalized symptomes weakness and fatigue mental changes unintended weight loss we

22、ight gain abnormal body temperaturehypersecretion of adrenal cortexsymptomes ophthalmic abnormalities abnormal skin pigmentation hirsutism gynecomastia galactorrhea abnormal appetite diarrheasymptomes anemia tachycardia and bradycardia polyuria amenorrhea or oligomenorrhea infertility bone pain and

23、pathologic fracturehyposecretion of thgh = pituitary dwarfismphysical and laboratory examination and diagnosishistory and physical examination many syndromes of hormonal excess or deficiency display manifestations that are readily apparent at the time of initial presentation, e.g., severe thyrotoxic

24、osis and cushings syndrome. in other instances, the clinial presentation is more subtle and the physician must rely on laboratory testing to establish a diagnosis.laboratory testing the level of free rather than total hormone is usually the best index of the effective hormone concentration in plasma

25、. a measurement of the 24-h urine free cortisol usually provides a reasonable estimate of the integrated levels of free plasma hormone.-75-75-50-50-25-250 025 2550 5075 75100100151520202525303035354040clinical interpretation the clinicians must remember that in both mormal subjects and patients with

26、 endocrine and other diseases, hormone levels are extensively regulated. for instance, plasma insulin levels should be evaluated in relation to the plasma glucose concentration, and pth levels should be considered in relation to serum calcium levels.clinical interpretation since cortisol production

27、integrated over a 24-h period is increased in cushings syndrome, the 24-h urinary free cortisol provides a more accurate index of cortisol hypersecretion.clinical interpretation sometimes the significance of hormone levels can be evaluated only by the simultaneous measurement of more than one hormon

28、e. for instance, with progressive damage to the thyroid hormones, secretion of tsh increases in a compensatory fashion so that normal plasma levels of the thyroid hormones may be maintained.clinical interpretation plasma estrogens are low in ovarian failure. if ovarial failure is due to disease of t

29、he ovary, plasma gonadotropins will be elevated. if ovarian failure is secondary to pituitary or hypothalamic disease, plasma gonadotropin levels will be normal or decreased.dynamic testing provocative testing assesses the ability of a gland to respond to stimuli as an index of its reserve capacity.

30、 insulin induced hypoglycemia is used to assess the secretory ability of cells that produce growth hormone.tests that provide indirect information diagnosis of diabetes mellitus and assessment of therapy depend on measurement of plasma glucose rather than insulin levels. it is helpful to follow the serum calcium levels in hyperparathyroidism and the serum potassium levels in primary aldosteronism.tests that provide indirect information for instance, serum sodium is almost always greater than 139meq/liter