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Help us decide who to hire as a
Cell/Molecular Biology Lecturer
Dr. Eva Ma will visit Wednesday January 20.
Teaching presentation 2-3 pm, in DISC 464 (please come!)
Dr. Alaron Lewis will visit Wednesday January 27.
Teaching presentation 2-3 pm, in DISC 464 (please come!)
Image: cargocollective.com/synapses/neurodevelopmental-biology-interview-michael-barresi
BBio 351 –
January 20, 2016
Outline for today:
• The hypothalamic-pituitary axis (7.3)
•
•
•
•
Anatomy, including pituitary parts
Tropic hormones and feedback loops
End-of-chapter questions
Thyroid hormones (7.5)
• Effects on metabolism
• Rat experiments
• Human disorders
• Synthesis, storage, secretion
Figures: A.D.A.M. & Anaesthetist.com
What is “thyroid hormone”?
Overall function of thyroid hormones:
Effects on cellular
metabolism:
thyroid regulates
Na+/K+ pump
EXTRACELLULAR
FLUID
3 Na+
Sodium–
potassium
exchange
pump
2 K+
ATP
ADP
CYTOPLASM
Martini Figure 3-19
(like Sherwood Figure 3-14)
Effects on cellular metabolism:
thyroid regulates non-shivering thermogenesis (NST)
http://people.duke.edu/~sc9/pics/figure1.jpg
(see also Sherwood Figure 15-19)
What kinds of animals would benefit most from NST?
Simulated rat experiments
“PhysioEx” supplement to Marieb lab manual (2014)
Simulated rat experiments
• Part 1: Determining the basal metabolic rates (BMR)
• 3 rats: normal, thyroidectomized, hypophysectomized
• Thyroidectomy =
• Hypophysectomy =
• Measure BMR as O2 consumption rate (mL O2 per kg per hour)
• O2 consumption is determined in a closed “metabolic chamber”
• Part 2: The effect of thyroxine on metabolic rate
• Treatment is applied for 1-2 weeks
• Part 3: The effect of TSH on metabolic rate
• Treatment is applied for 1-2 weeks
• Part 4: The effect of propylthiouracil on metabolic rate
• Propylthiouracil (PTU) is a drug that inhibits thyroxine production by
blocking the attachment of iodine to tyrosine residues
• Treatment is applied for 1-2 weeks
“PhysioEx” supplement to Marieb lab manual (2014)
Experimental outcomes
Experiment
Normal
Thyroidectomized
Hypophysectomized
1. Basal Metabolic
Rate (BMR)
“baseline”
(1700 mL
O2/kg/hr)
↑, ↔, ↓?
↑, ↔, ↓?
2. Thyroxine
treatment
↑, ↔, ↓?
(vs. row 1)
↑, ↔, ↓?
(vs. row 1)
↑, ↔, ↓?
(vs. row 1)
3. TSH treatment
↑, ↔, ↓?
(vs. row 1)
↑, ↔, ↓?
(vs. row 1)
↑, ↔, ↓?
(vs. row 1)
4. PTU treatment
↑, ↔, ↓?
(vs. row 1)
↑, ↔, ↓?
(vs. row 1)
↑, ↔, ↓?
(vs. row 1)
Thyroid disorders (overview)
Category
Causes
Thyroid function diagnostic tests
niddk.nih.gov
Therapy for thyroid disorders?
• Hypothyroidism
• Hyperthyroidism
Synthesis, storage, secretion of T3 & T4
Sherwood Figure 7-17
Synthesis, storage, secretion – key aspects
• Thyroid follicle
• Colloid
• Thyroglobulin
• Iodine
Stimulation of thyroid gland by TSH
• Review: where is TSH produced?
• What kind of hormone is TSH?
(polypeptide, amino acid derivative, steroid)
• 3 key effects of TSH on thyroid follicular cells?