1. Endocrine Reproduction Introduction
Dr. Mohammed Kalimi
Endocrine Reproduction Introduction

4. Biosynthesis of hormones:
The peptide hormones are synthesized by rough endoplasmic reticulum as a pre-pro-hormone
The steroid and amine hormones are synthesized from cholesterol and tyrosine respectively through a series of enzymatic reactions by smooth endoplasmic reticulum, and mitochondria

5. Release of hormone Excitation secretion coupling and release
↑ Intracellular calcium
↑ cAMP
↑ Activation of microtubular or microfilament system
↑ Fusion of membrane of the secretory granule with that of the cell
↑ Ejection of the hormone by exocytosis

6. Hormone release Secretion rate or production rate of a hormone:
n moles / minute or ng / minute
Plasma concentration of a hormone:
n moles / mL or ng / mL

7. Transport of hormones in blood:
Bound to carrier proteins: Steroid and thyroid hormones circulate bound to specific globulins
Unbound or free: With few exceptions (IGF-I), peptides and protein hormones circulate unbound

8. Inactivation of hormones:
By specific target tissues (internalization and lysosomal degradation)
By liver and kidneys
By both of the above

9. Measurement of hormones:
Radioimmunoassay
Localization of hormones in tissues of origin and action: Immunocytochemistry

10. Control of hormonal secretion
Positive or Negative Feedback
Neuro-Endocrine Integration
Neuronal Control (dopaminergic, adrenergic,cholinergic)
Sleep-wake cycle, menstrual cycle, diurnal rhythm

12. Major function of hormones:
Initiates, mediates and regulates the processes of growth, differentiation, development, maturation and aging
Maintenance of homeostasis, fluid and electrolyte balance (Na+, K+, Ca++, glucose, water )
Regulation of cellular metabolism (fats, carbohydrates, proteins)
Sexual development and function, lactation and behavior

13. Malfunctioning of the endocrine system:
Primarily caused by:
Overproduction of a hormone (hyperfunction)
Underproduction of a hormone (hypofunction)
Unresponsiveness of target organ (lack of receptor, etc.)
Production of abnormal hormone

14. Neuroendocrinology Similarities between the two:
Each synthesizes and releases specific chemical agents which are capable of influencing another cell by interacting with specific receptors
Both neurons and endocrine cells generate electrical potentials and can be depolarized

15. Neuroendocrinology Differences between the two: Nervous system:
Specific chemical agents released are disseminated only a very short distance
System is fast acting
Actions are relatively short-lived
Operates with point to point precision
Affects only glandular secretions and muscular contractions

16. Neuroendocrinology
Endocrine system:
Specific chemical agents are released and carried via the blood stream throughout the whole body
System is slow acting
Actions are relatively long-lived
Affects a whole variety of cell types

18. Hypothalamus Thyroid-stimulating-hormone-releasing-hormone (TRH)
Corticotrophin-releasing-hormone (CRH)
Luteinizing-hormone-releasing-hormone (LHRH)
Growth-hormone-releasing-hormone (GHRH)
Somatostatin
Dopamine

19. Anterior Pituitary Hormones
Growth Hormone (GH)
Prolactin
Thyroid Stimulating Hormone (TSH)
Adrenocorticotrophic Hormone (ACTH)
Luteinizing Hormone (LH)
Follicle Stimulating Hormone (FSH)
Melanocyte stimulating Hormone (MSH)

20. Posterior Pituitary Hormones
Oxytocin
Vasopressin or Anti Diuretic Hormone (ADH)

22. TH Gland Thyroid Hormones (T3 and T4): Follicular cells
Calcitonin : Parafollicular cells

23. Adrenal Cortex Glucocorticoids : Cortisol and Corticosterone
Aldosterone

24. Para Thyroid Gland
PTH

25. Adrenal Medulla
Epinephrine and Norepinephrine

26. Pancreas
Insulin
Glucagon
Somatostatin

27. Skin, Liver, and Kidney
Vitamin D

28. Gonads
Testis: Testosterone
Ovaries: Estrogen, Progesterone

29. Placenta Human Chrionic Gonadotropin (hCG)
Human Placental Lactogen (hPL)

30. Steroid Hormone Mechanism
Estrogens
Androgens
Progesterone
Aldosterone
Glucocorticoids
Thyroid Hormones
Vitamin D
Vitamin A

32. Cyclic AMP ( cAMP) MechanismLH
FSH
TSH
ACTH
ADH (via V2 Receptor)
hCG
MSH
CRH
Catecholamines
Calcitonin
Glucagon
PTH

36. cAMP Inhibitory ( cAMP) mechanism
Somatostatin
Dopamine

37. The Calcium-Phospholipid mechanism
GnRH (LHRH)
TRH
Angiotensin II
ADH via the V1 receptor

39. Associated Tyrosine Kinase mechanism (Janus Kinase)
Prolactin GH

40. Intrisic tyrosine phospho-kinase mechanism
Insulin
IGF-I

41. Hypothalamus Calcium-Phospholipid Mechanism TRH, LHRH
↑Adenylyl Cyclase, ↑cAMP Mechanism
CRH,GHRH
Adenylyl Cyclase,cAMP Mechanism
Somatostatin
Dopamine

42. Anterior Pituitary Hormones
Janus Kinase (associated tyrosine kinase) Mechanism
GH, Prolactin
↑ cAMP Mechanism
TSH, LH, FSH, ACTH, MSH

43. Posterior Pituitary Hormones
Calcium-Phospholipid Mechanism
Oxytocin, ADH (via V1 receptor)
↑cAMP Mechanism
ADH (via V2 receptor)

44. ↑ cAMP mechanism Adrenal Medulla Epinephrine and Norepinephrine
Parathyroid Gland
PTH
TH Gland (Parafollicular Cells)
Calcitonin
Pancreas (α Cells)
Glucagon
Placenta
hCG