1. Basics of Endocrinology
Kathleen Colleran MD
Associate Professor of Medicine

2. Definitions
Endocrinology- the study of hormone and glandular abnormalities- diabetes, thyroid problems, and circus performers
Hormones-biologically active substances secreted by glands.
Endocrine- hormones that have a biological effect far away.
Paracrine- hormones that have a biological effect nearby.
Autocrine- hormones that have a local effect

5. Hormone Functions
Growth and development: Thyroid, GH, Sex Steroids, Cortisol
Reproduction: Estrogen, Testosterone, FSH, LH, Thyroid
Homeostasis: Thyroid, Cortisol
Changes in environment: Cortisol, Thyroid Aldosterone

6. Interaction of Hormones
Gluco
neo
gensis
Organ
growth
Protein
synthesis
temp
metab HR
Sex steroids
T-4 GH
Skeletal
growth

7. Hormone Classification
Proteins-thyroid stimulating hormone, insulin, parathyroid hormone
Amino acids-thyroid hormone, epinephrine
Steroids-cortisol, aldosterone, testosterone

8. Mechanism of Action of Hormones
Circulate in blood stream bound to transporter proteins or free
Free hormone is the active hormone
Enter cells to alter biological activity

9. Hormone Action peptide and cathecolamines
TSH
TSH
TSH R
2nd
messenger
protein
T-4
effect I

10. Hormone Action Steroid, Thyroid
TBG
T-3 R
T-3 R
T-3
Increased HR
-receptors

11. Hormone Regulation Feedback loops Circadian Rhythms
Receptor specificity
Receptor concentration

12. Endocrine Rhythms: "It don't mean a thing if it ain't got that swing!"
ACTH LH GH
0800
2000
0800
0800
2000
0800
0800
2000
0800
Cortisol
TSH
Testosterone
0800
2000
0800
0800
2000
0800
0800
2000
0800

13. Feedback Regulation of the Anterior Pituitary:
Hypothalamus - -
Short Loop
Feedback ? + -
Long Loop
Feedback -
Pituitary +
Target Organ

14. The $- Subunit Confers Specificity:
$ - Subunits
hCG LH
TSH
FSH

15. Biosynthesis of ACTH from POMC:
Pro-Opiomelanocortin (POMC)
$-LPH
N-Terminal Peptide
ACTH
LPH
$-Endorphin
"-MSH

16. Clinical Endocrinology
Hypofunction of a gland
Hyperfunction of a gland
Receptor defect
Second messenger defect

17. Endocrine Hypofunction
Congenital defects in hormone biosynthesis
Autoimmune destruction of glands
Surgery or trauma to glands
Infiltration by tumors, infection

18. Endocrine Hyperfunction
Hormone secreting Pituitary tumor
End organ secreting tumor
Autoimmune disease
Inflammation/Infection
Iatrogenic/Facticious
Ectopic hormone secreting tumor

19. Assessment of Glandular Activity
Measure the end organ hormone
Measure the pituitary regulating hormone
Suppression tests-to evaluate for hormone overactivity
Stimulation tests-to evaluate for underactivity
Imaging studies

20. The Players Other endocrine organs endothelial vascular cells
adipocytes
heart
bone
liver
kidney
????
Hypothalamus

22. Growth Hormone Actions:
Somatostatin +
GHRH - GH +
IGF-1,
Insulin Antagonism
Growth
Growth, Insulin Antagonism
Lipolysis

23. A Guy with Acromegaly:

25. Normal pituitary coronal

26. Pituitary adenoma

27. Optic Chiasm

29. Thyroid Gland (End Organ)
Located in anterior neck
Produces thyroid hormone
Regulates energy, metabolism, temperature, growth, development
Regulated by Pituitary and Hypothalamus

30. Figure  The dramatic case of Maria Richsel, the first patient to have come to Kocher’s attention with postoperative myxedema following total thyroidectomy. A. The child and her younger sister before the operation. B. The changes nine years after the operation. The younger sister, now fully grown, contrasts vividly with the dwarfed and stunted patient. Also note Maria’s thickened face and fingers, which are typical of myxedema. Because of this and other patients with the same problem, Kocher stopped performing total thyroidectomies. For this work, demonstrating the physiological importance of the thyroid gland in man, Professor Kocher was awarded the Nobel prize. From: Kocher T. Uber Kropfextirpation und ihre Folgen, Arch Klin Chir 29:254, 1883, with permission.

31. Congenital Hypothyroidism
Cretinism
Stunted growth
Neurological/ cognitive defects/mental retardation
Infantile appearance-puffy face protuberant abdomen

32. Figure Map showing world wide distribution of iodine deficiency disorders (IDD) in developing countries.

33. Figure 20-9.Three women of the himalayas with typical endemic goiters.

34. Grave’s Ophthamopathy

36. Figure 10-5.
(a) This MRI image from a patient with Graves' ophthalmopathy provides a coronal view of the eyes.  In this depiction the muscles appear white, and are enormously enlarged, especially in the left eye.
(b) In this transverse view the enlarged muscles are seen (appearing dark against the light fat signal) and the exophthalmos is apparrent.

37. I123 uptake and scan

38. Adrenal Glands Locate above the kidneys
Aldosterone, cortisol, sex steroids, epinephrine
Regulates, vascular tone, stress, metabolism, fight or flight response

39. Cushing’s

40. Cushings
Striae, hirsutism, central adiposity
Buffalo hump

41. Adrenal Adenoma

42. 2 years Post op

43. Gonads

44. XX male A variant of Klinefelter's Recombination event during meiosis
The SRY gene combines with an X chromosome
XX+ SRY
SRY

45. Y chromosome SRY gene product Paramesonephric (mullerian) ducts
Undifferentiated
gonad
Mullerian
inhibiting
substance
or Absent gonad
Active
regression
Testis
Ovary
Paramesonephric
(mullerian) ducts
Mesonephric
(wolffian) ducts
Testosterone
Passive
development
Mesonephric
(wolffian) ducts
Later
estrogenic
support
Passive
regression
Active
development
Ductus deferens
Uterine tube
Uterus
Seminal
vesicle
Epididymis
Ovary
Upper third
of vagina
Testis
Carlson, BM (1999) Human Embryology
and Developmental Biology, 2nd ed.

46. Pearls If you think its over active try to supress
If you think its under active try to stimulate
Never get imaging before biochemical diagnosis

47. Conclusions
Hormones are essential for normal growth, development, metabolism, energy, reproduction etc.
Hormones are tightly regulated by multiple systems
Both over and underproduction of hormones leads to clinical disease

48. Finally Hormones You can’t live with them but…
You can’t live without them!