Lecture 4:
Overview:
Cytoplasmic: steroids
Nuclear, Thyroid, Estrogen, Vit D, PPar, etc
Hormone response elements
Heat shock Proteins
Ligand binding domain
Heat shocked proteins:
· Have many functions: bind to hydrophobic portions of proteins when exposed to surface and also protect proteins form further unfolding and aggregating
· The amino domain of the peptide, there is a tarns activation domain, in the middle there is a DNA binding domain, and near the carboxy terminal there is the bound HSP
o DNA binding domain have zinc fingers which cause the binding of the activated receptor with a hormone to DNA
§ The hormone with the gene response elements will turn on the gene
o A nuclear translocation sequence
· Hormone response elements
· The receptors for thyroid hormone vitamin D and PPARs and estrogen
Hypothalamus
· Contains receptors that detect changes in osmolarity of plasma and secrete or inhibit secretion of hormone adh
o Responses to blood changes and volume
· Regulates appetite
· Biological clock: circadian rhythms
o Secrete certain hormones in pulses
· Contains thermoregulatory center
o Receives input from peripheral and other thermal receptors
o Has a set point and can have a variety of reflexes for these changes
§ Fever is caused by increase of cyclocandins which increase COX
· Aggression, rage
· Sex drive, gonad regulation
· Adrenal cortex
· Thydroid
· Anterior pituitary
o GH, Prolactin
o ACTH, TSH, LH, FSH
· Posterior pituitary
o ADH(vasopressin), Oxytocin
Pituitary gland is also called the Hyposis
· Anterior pituitary is a real endocrine gland that secrete protein hormones.
o The hormones are secreted by groups of cells that are named by what they secrete
§ GH(somatostatin) is secreted from somatotrophs
§ Lactotrophs- prolactin
§ Thyrotrophs- TSH
§ Gonadotrophs- FSH + LH
§ Corticotrophs-ACTH
· Posterior has axons of neurons that are in the hypothalamus
o This is where ADH and Oxytocin are secreted into the capillaries in the posterior pituitary
· The bone where the pituitary sits is called the spinoid bone
o Forms the roof of the nose and some of the floor of the eyes
· The name of the structure in which the pituitary gland sits is called the “Turkish saddle”, sellaturcka
· The optic chiasm is right in front of the pituitary stalk, this is where some optic nerve fibers cross
o If there is a tumor near the pituitary may cause the loss of peripheral vision
Portal vein
· Arteriole->Capilaries->Venule->Vein->Venule->Capilarry->Venule->Vein->Heart
· It’s a mean of transporting materials without diluting it with the rest of the blood
· The second acpilary bed gets first shot at the nutrients released from the first capillary bed
· Found in the gastrointestinal tract… hepatic portal vein
· Also found in the anterior pituitary
o First capillary bed is in the hypothalamus then second capillary bed is in the anterior pituitary
Hormones
· Oxytocin – milk ejection reflex that stimulate this releases is the suckling of nipple
o Secreted during sexual orgasm
o Also causes uterine contraction
o Positive feedback loop
§ Increase oxytosin causes increasing push of fetus towards cervix, which causes increases cervix stretch which causes more release of oxytocin
· ADH (Vasopressin)
o Stimulated by increased plasma osmolarity
§ The increase of ADH affects the collecting duct of nephron by adding more aquaporins to the collecting duct
§ Aquaporins are water channels
o Increase ADH causes aquapoin 2 inserted in membrane which reabsorbs H2O that lowers plasma osmolarity increases blood pressure and volume therefore stops secretion of ADH
o ADH is stimulated by increase plasma osmolarity, decreased blood pressure, decreased blood volume
§ Stimulates thirst as well
