CSB325 Lecture 8 Review Notes

6 Pages
120 Views
Unlock Document

Department
Cell and Systems Biology
Course
CSB325H1
Professor
David Lovejoy
Semester
Fall

Description
CSB325 Lecture 9 – Energy and Stress Glucose metabolism GHRH and PACAP (paralogues)  somatotrophs in the anterior pituitary GH - Hexokinase (glucose  glucose-6-phosphate) - Stomach  ghrelin (direct)  positive feedback on somatotrophs (GH) - Glycogen synthetase (glucose-6-phosphate  glycogen) - Glucose-6-phosphatase (glucose-6-phosphate  glucose - Adipocytes  leptin (indirect)  positive feedback on GH-releasing factors (NPY, bombesin, CCK)  positive feedback on somatotrophs (GH) Pancreas - Endocrine component - Somatotrophs  activin (short-loop positive feedback)  positive o Islets of Langerhans secrete insulin and glucagon feedback on somatotrophs (GH) - Somatotrophs  GH (positive autoregulation)  positive feedback on - Exocrine component o Ductile cells secrete bicarbonate somatotrophs (GH) o Acinar cells secrete digestive enzymes - Liver  IGF-I & IGF-II (long-loop negative feedback)  negative feedback on somatotrophs (GH) Distribution of insulin-, glucagon-, and somatostatin-containing cells - Rat islet GH-releasing factors o Glucagon-containing cells (clustered) and somatostatin- - GHRH containing cells (clustered) are at the periphery of the islet, and - PACAP insulin-containing cells (dispersed) are centrally located - GnRH, dopamine, TRH - Human islet - NPY, bombesin, CCK o The islet is divided into smaller subunits GH-inhibiting factors o Each subunit contains glucagon-containing cells (clustered) and - Somatostatin (SRIF) somatostatin-containing cells (clustered) at the periphery of the - Serotonin, norepinephrine, glutamate islet, and insulin-containing cells (dispersed) are centrally located Actions of GH on carbohydrate, lipid, and protein metabolism Endocrine cells in the islets of Langerhans of the pancreas - Liver - Alpha cells (A cells)  Glucagon, GLP-1 and GLP-2 o ↑ VLDL secretion - Beta cells (B cells)  Insulin, C-peptide, Amylin, GABA, PTHrP o ↑ HL activity - Delta cells (D cells)  Somatostatin o ↓ PPARα expression - PP cells (F cells)  Polypeptide o ↑ production and uptake of IDL, LDL, HDL Insulin o ↑ protein synthesis - Stimulated by glucose - Bone o ↑ mineral accretion - ↑ glucose uptake - ↑ glycogen formation o ↑ bone mass - ↑ lipogenesis - Muscle o ↓ glucose uptake - ↑ lipid accumulation - ↑ amino acid uptake o ↑ LPL activity - ↓ glycogen mobilization o ↑ β-oxidation o ↑ protein synthesis - ↓ amino acid mobilization - ↓ gluconeogenesis - Adipose - ↓ lipolysis o ↑ lipolysis  ↓ lipogenesis Glucagon - Stimulated by fasting, stress, protein-rich diet  ↓ re-esterification of FFA - Major functional antagonist of insulin  ↓ glucose uptake  ↓ body fat mass Adrenal gland - Adrenal medulla (called head kidney in fishes) o Made up of nervous tissue o Produces catecholamines (epinephrine, norepinephrine) - Adrenal cortex (called interrenal gland in fishes) o Made up of epithelial tissue o Produces steroids (cortisol, corticosterone, aldosterone, testosterone, estradiol, glucocorticoids) - Epinephrine o Activated by emotional stress  Emotional stress tends to utilize glucose resources and protect adipose supplies o ↑ glycogenolysis (glycogen breakdown) o ↑ glycolysis (glucose breakdown) o ↑ blood glucose - Norepinephrine o Activated by physical stress (e.g., hypotension, hypoglycemia, blood loss, hypoxia, cold, fright)  Physical stress tends to utilize adipose resources and protect glucose supplies o ↑ lipolysis (FFA breakdown) o ↑ blood FFA Hypothalamus-pituitary-thyroid (HPT) axis Hypothalamus-pituitary-adrenal (HPA) axis - CRF is secreted into the vasculature at the median eminence by the paraventricular nucleus in the hypothalamus - TRH is secreted into the vasculature at the median eminence by the paraventricular nucleus in the hypothalamus Interaction between CRF and TRH Interaction between CRF and NPY - CRF and TRH can have positive and reciprocal actions on the release of each other in the PVN Stress responses Supraoptic nucleus (SON) - Three basic phases - Magnocellular cells o Phase 1 = catecholamines o AVP containing cells, which project to the posterior pituitary  Epinephrine (e.g., osmoregulatory response)  Norepinephrine  stimulates HPA axis Note: Vasopressin and oxytocin released from the PVN are associated with the o Phase 2 = cortisol activity stress response, but vasopressin and oxytocin released from the SON are associated  ACTH with osmoregulatory respons
More Less

Related notes for CSB325H1

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit