BIOL 2P93 Lecture Notes - Aromatase, Breastfeeding, Adrenocorticotropic Hormone

40 views3 pages
Published on 4 Feb 2013
Course
Professor
The Hypothlamo-pituitary Unit
I. Introduction
a. Pituitary (“mucus”) = hypophysis (“small/under growth”)
b. Brain acts as an endocrine gland thru hypothalamus via the pituitary gland
c. Pituitary has a portal system—(vessels w/ capillary network on either side); blood
flows from neurohypophysis to adenohypophysis via the vessels & then out to
body
II. Neurohypophysis—(posterior pituitary) releases ADH & oxytosin; hormones
synthesized in hypothalamus & stored/released from pituitary
a. ADH (arginine-vasopressin)
i. Neurophysin II—transport protein carrying ADH from hypothalamus to
neurohypophysis
ii. circulates as free peptide; ½ life = 2 min
iii. Fxn—increases H2O absorption from renal tubuli
iv. Stimuli
1. changes in blood volume—volume receptors in carotid sinus, L
atrium, & aortic arch; exponential relationship (quadratic) between
ADH release & blood volume loss
2. changes in serum osmolality—↑ osmolality => ↑ ADH secretion;
linear relationship+
3. fear & pain
b. Oxytocin
i. Neurophysin I—transport protein carrying oxytocin from hypothalamus
to neurohypophysis
ii. circulates as free peptide; ½ life = 2 min
iii. Fxn—stimulates contraction of uterine mm. & letdown of milk
iv. Stimuli—parturition, suckling, coitus
III. Adenohypophysis—(anterior pituitary)
a. Cytology of adenohypophysis
i. Somatotropes (GH-secreting) ~50%
ii. Lactotropes (PRL-secreting) ~15-25%
iii. Corticotropes (ACTH secreting) 15-20%
iv. Gonadotropes (LH & FSH secreting) 10-15%
v. Thyrotropes (TSH secreting) 3-5%
b. PIT-1 Gene
i. transcription factor that regulates (characterizes) pituitary stem cells
ii. gives rise to GH, PRL & TSH hormones => determines differentiation of
somatotropes, thyrotropes, & lactotropes
IV. Hypothalamic Hypophysiotropic Hormones
a. Growth Hormone releasing hormone (GRH)
i. Fxn—Induces production of GH from pituitary; sleep induction
ii. Two forms, both are equally active; ½ life = 5 min
iii. Binds to a GPCR
iv. Part of H-P-growth hormone axis
b. Somatostatin
1
Unlock document

This preview shows page 1 of the document.
Unlock all 3 pages and 3 million more documents.

Already have an account? Log in

Get OneClass Notes+

Unlimited access to class notes and textbook notes.

YearlyBest Value
75% OFF
$8 USD/m
Monthly
$30 USD/m
You will be charged $96 USD upfront and auto renewed at the end of each cycle. You may cancel anytime under Payment Settings. For more information, see our Terms and Privacy.
Payments are encrypted using 256-bit SSL. Powered by Stripe.