Flashcards in Endocrine Physiology - Theoretical Questions (no Repro.) Deck (104)
What are the Hormones released by the PVN? to where? What are they Related to or Releasing?
CRH and TRH to Adenohypophysis Basophil cells for POMC and TSH.
Oxytocin to neurohypophysis - Suckling, Birth, Ejaculation.
What is the Hormone released by the SON? to where? What regulates its release?
ADH to neurohypophysis.
Blood volume↓, Osmolarity↑, Pain↑, Ethanol↓, AT-II↑
TRH - What elevates its release?
Pregnancy and Low temperature
CRH - What elevates its release?
Fever, stress and Hypoglycemia
What gets released from the Preoptic Nucleus? to where?
GnRH to the Adenohypophysis Basophil cells
What gets released from the Arcuate Nucleus? to where?
GHRH and PIH to Adenohypophysis Acidophil cells
What are the passages for Hormones or Hormone releasing factors in the Hypothalamo-Hypophyseal axis?
1)PVN+SON to Hypothalamo-Hypophyseal tract to Neurohypophysis Herring bodies for Peptide storage.
2)PVN, Preoptic and Arcuate to Hypophyseal Portal arteries to Acidophils and Basophils of Adenohypophysis.
What are the Hormones of the GH/PRL family? which cells secrete them?
Growth Hormone - Somatotroph cell
Prolactin - Lactotroph cells
Human chorionic Somatotropin and (p)GH - Placenta
What are the Hormones of the Glycoprotein family? which cells secrete them?
Thyroid Stimulating Hormone - Thyrotropic Cells
Follicle Stimulating Hormone - Gonadotropic Cells
Lutenizing Hormone - Gonadotropic Cells
Human Chorionic Gonadotropin - Placenta
What are the products coming from the Cleavage of Proopiomelanocortin? which cells secrete them?
Beta-Endorphin, melanocyte-stimulating Hormone and Adrenocorticotropic Hormone. POMC originates from Corticotropic Cells.
Hormone 4 important parts of definition:
1)Secreted by Glands (ADH and Oxytocin are exception)
2)Carried in blood
4)Small amount creates a large effect (10^-6 - 10^-12)
What is the effect of Somatostatin on GH and TSH?
It has a Gi receptor of the Thyrotroph and Somatotroph cells. Leads to inhibition of their release.
What is the effect of Dopamine on the Release of PRL?
What are the general factors Stimulating its release?
It inhibits it by Gi (D2R) mechanism. Dopamin in this regard is called PIH.
VIP, TRH and Baby Suckling all cause release.
What are the factors causing GH NOT to be released?
1)Somatostatin from PVN inhibits Somatotroph release
2)IGF-1 a - Negative Feedback to Somatotroph cell(GH)
3)IGF-1 a - Negative Feedback to Arcuate Nucleus(GHRH)
4)IGF-1 a - Negative Feedback to PVN to release SST
What other Hormone causes release of GH? (other than GHRH)
Ghrelin produced in stomach (hunger) causes Gq activation of GH.
What are the non-Hormonal Factors are causing release of GH?
2)Fasting, Extreme exercise, Stress
3)Alpha-2 Adrenergic Stimulation (Gi but activates)
Mechanism of GH activity:
Associated Tyrosine Kinase Receptor:
JAK2-(P) - STAT5-(P) - expression of Somatomedins
What are the direct effects of GH? (Acute)
1)Glucagon↑ - [Glucose]↑
2)Lipolysis↑ - [FFA]↑
3)Muscle AA Uptake↑ - Protein Synthesis↑
4)Somatomedin production - IGF-1↑
What are the Indirect effects of GH? (Chronic = IGF-1↑)
1)Bone length growth
What prevents desensitization of GH receptors?
What is the mechanism?
Pulsatile secretion of GH - every 2 hours
Circadian secretion - Largest 1hr after sleep
What are the consequences of overproduction of GH in Childhood?
What are the consequences of overproduction of GH in Adults?
What are the consequences of deficiency of GH in Childhood?
What are examples for Positive feedback?
1)During Ovulation Estradiol from ovary causes Increase in GnRH allowing more FSH .
2)Thrombin activating factors V, VIII, XI leading to Prothrombinase formation.
What are basic definitions of Primary, Secondary and Tertiary Hormone Disorders?
Primary - Originates in Hypothalamus
Secondary- Originates in Hypophysis
Tertiary - Originates in the Gland
What are the layers of the adrenal cortex?
Which hormones are produced in each level?
Outer) Z. Glomerulosa - Mineralocorticoids - Aldosterone
Middle) Z. Fasciculata - Glucocorticoids - Cortisol
Inner) Z. Reticularis- Androgens- DHEAS and Androstenedione.
What is the rate limiting step of the synthesis of Steroid hormones? Catalyzed by? What is required for it?
1)Cholesterol to Pregnenolone.
2)CYP11A1 (SCC) in the mitochondria.
3)ACTH activates StAR protein for entrance of Cholesterol to mitochondria.
What causes the release of Steroid hormones from storage?
Cholesterol is the Stored form (Lipid droplets) that is activated by entering the Mitochondria and allowing for conversion to Steroids which are released as formed by Simple diffusion to blood (Hydrophobic).
What are the CYP numbers for the formation of Aldosterone?
(SCC - 3HSD )- 21 - 11