1. Hypothalamus and Pituitary Function
Chemistry CLS415 Didactics
Module 1
Introduction to Endocrinology: Basic Concepts

2. Objectives: Define the following terms: Exocrine system Receptors
Hormone
Target organ
Endocrine system
List the major endocrine glands and the hormones they secrete
Describe the action of hormones in terms of their:
Regulatory and physiologic functions
Morphologic action
Integrative action
Exocrine system
Receptors

3. What is Endocrinology? Study of intracellular and
extracellular communication by
hormones of the endocrine system

4. Transmission of Information
Occurs through several systems or networks
Nervous System
Immune System
Hormonal System
Others
Endocrine system is controlled by its linkage with CNS through hypothalamus and pituitary glands

5. The Endocrine System A ‘fine-tuned’ communication system
Maintains cellular homeostasis
Body metabolism
Growth and development
Reproduction

6. Major Endocrine Glands

7. Hypothalamus

8. What are Hormones? Chemical messengers
Interact with target organs by specific receptors
Illicit biologic response
Different modes of transport and action
Example:
Endocrine Paracrine
Exocrine Autocrine
Juxtacrine Neuroendocrine
Neurocrine Neurotransmission

9. Endocrine vs Exocrine
Pancreas: insulin Pancreas: amylase & lipase

10. Hypothalamus Releasing Hormones (factors)
Inhibiting Hormones (factors)
Produce ADH and Oxytocin
Act on anterior pituitary gland
Release Tropic Hormones
Stored in posterior pituitary gland

11. Stimulating (tropic) Hormones
Stimulating = tropin = trophic = tropic
Stimulating hormones are specific to
a particular target organ or target cell

12. Stimulating (tropic) Hormones
Gonadotropin: stimulates the gonads
Target gland = testes and ovaries
Thyrotropin: stimulates the thyroid
Target gland = thyroid gland
ACTH = adrenocorticotropic hormone:
stimulates the adrenal gland
Target gland = adrenal cortex

13. Stimulating (tropic) Hormones
Stimulating hormones interact with their target glands through receptors
Membrane receptors:
Located on the cell membrane
Interact with protein-type hormones
Cytoplasmic receptors:
Located in the cytoplasm of the cell
Interact with steroid-type hormones

14. Site of hormone’s action (target)
Table, page 2 of handout
Endo Gland
Hormone
from endocrine gland
Site of hormone’s action (target)
Biological response of target
Anterior Pituitary
TSH
ACTH
FSH, LH GH
MSH
Prolactin
Thyroid gland
Adrenal cortex
Ovary, testis
Body as a whole
Skin
Mammary glands
Form T3,T4
Form Steroid
Sexual maturation
Bone/muscle
Darken skin
Lactation
tropic hormones

15. Pituitary Gland (hypophysis)
Posterior
pituitary
Anterior
pituitary

16. Table, page 2 of handout Endo Gland Hormone from endocrine gland
Site of hormone’s action (target)
Biological response of target
Posterior Pituitary
ADH
Oxytocin
Renal tubules, arterioles
Uterus,
Breast tissue
Reabsorb H2O
 BP
Contraction
Milk ejection

17. Table, page 2 of handout Endo Gland Hormone from endocrine gland
Site of hormone’s action (target)
Biological response of target
Thyroid
T3 and T4
Calcitonin
General body tissue
Bone
 O2 consumption,
 BMR
Inhibits calcium resorption (keeps calcium in bone)

18. Table, page 2 of handout Endo Gland Hormone from endocrine gland
Site of hormone’s action (target)
Biological response of target
Adrenal Cortex
Steroid hormones:
Cortisol
Aldosterone
General body tissue
Kidney tubules (DCT, collecting)
Carbohydrate, protein, fat metabolism
Salt and water balance

19. Table, page 2 of handout Endo Gland Hormone from endocrine gland
Site of hormone’s action (target)
Biological response of target
Adrenal Medulla
Norepinephrine and Epinephrine
Epinephrine =
‘Fight or Flight’ hormone
Sympathetic receptors
Liver, muscle, fat
Stimulate sympathetic nervous system
Glycogenolysis, lipolysis

20. Regulatory and Physiologic Functions
Electrolyte and water balance
Aldosterone: Na+ (and K+, H+)
ADH: water reabsorption
Storage and use of nutrients
Insulin: carbohydrate (glucose) regulation
Cortisol: carbohydrate, protein, lipid

21. Morphogenic Action Synthesis of cellular compounds
Thyroid hormone
Catecholamines
Steroid hormones
Growth and development
GH (growth hormone)
Thyroid hormones

22. Morphogenic Action Sexual maturation and reproduction
Gonadotropins (LH and FSH)
Estrogen (female sex hormone)
Testosterone (male sex hormone)
HCG (human chorionic
gonadotropin)

23. Integrative Action
No hormone works alone!

24. Integrative Action