Endocrinology and Reproduction Flashcards
Increase insulin production
Rise in: glucose, aa, FA Parasympathetic N S - Aco Sulfonylurea Obesity, insulin resistance Beta- adrenergic, GI hormones, GH, cortisol, glucagon
Mechanism of glucose stimulation of insulin production
Glucose>100mg/dl - transported by GLUT2 - phosphorilated - oxidated to form ATP - close ATP sensitive K channels - depolarization of membrane - open Ca channels - move lysosomes w insuline and peptide C to membrane - exocytosis.
Inhibit insulin production
Sympathetic NS Reduction in glucose Somatostatin Alfa-adrenergic activity Leptin
Withdraw of which hormone causes mentruation?
Progesterone
Immunization to produce antibodies that would bind to FSH and negate its activity is being investigated as a potential male contraceptive. Men immunized in this manner would exhibit ____.
decreased serum inhibin levels
The two essential hormones for the production of sperm (spermatogenesis) are _____.
FSH and testosterone
In males and females, secretion of luteinizing hormone (LH) by the pituitary is regulated by ____.
Gonadotrophin Releasing Hormone (GnRH)
In a female patient with an inactivating mutation of the estrogen receptor genes (both alpha and beta), one would expect _____.
1-low progesterone receptor number in breast tissue
B. high plasma estrogen concentration.
C. no mid-cycle LH and FSH surge.
Steroid hormones such as estrogen and progesterone _____.
A. freely diffuse through cell membranes.
In the first 8 days of the menstrual cycle, how does estrogen affect the release of FSH and LH from the pituitary?
B. Decrease
In the male and female gonad, ____ is converted to estrogen by aromatase activity.
A. androgen Correct 1.00
What hormone(s) are negatively regulated by inhibin B in the male and in the female?
A. FSH
In males and females what hormone(s) does kisspeptin regulate?
B. GnRH
What is the phenotype of a XY individual in which all forms of the enzyme, 5’alpha reductase, are inactive?
A. female
Insulin dependent glucose uptake occurs in which of the following sites?
A. kidney
B. skeletal muscle Correct
C. brain
D. cardiac muscle
Jane, a 23 year old female, presents with complaints of a 15 lb weight loss and periodic episodes of weakness 2 hours after eating. On examination you find her blood pressure is 120/80. Her laboratory data shows fasting hyperglycemia (glucose, 200 mg/dl). You suspect an endocrine pathology and request an RIA for the hormone _____.
E. insulin
Jane’s, 23 years old, complaining of weight loss and episodes of weakness 2 hours after meals. Laboratory results shows fasting hyperglycemia (glucose 200mg/dl) and confirm insulin is absent. You administer an oral glucose tolerance test. Her glucose tolerance test fails (400 mg/dL at 4 hours post ingestion) . You would classify this endocrine pathology as ______.
B. primary, pancreatic islet insufficiency.
Which of the following hormones is catabolic in its action?
E. cortisol and glucagon
During the fed state, nervous tissue derives most of its metabolic energy from:
A. glucose
During the fasting state, most of the circulating glucose is due to the _____which breaks down glycogen to glucose.
A. liver
Which of the following hormones stimulates lipolysis (break down of fat)?
A. insulin
B. aldosterone
C. insulin like growth factor 1
D. epinephrine - correct
Epinephrine acts in a synergistic manner to regulate blood levels of glucose by inhibiting:
A. insulin secretion
A patient with diabetic ketoacidosis hyperventilates because____.
C. elevated plasma H+ concentration stimulates respiratory centers.
At the end of a strenuous workout lasting 3 hours, John’s blood glucose levels were 70 mg/dL. Which of the following hormones would be increased in his blood at this time?
E. cortisol, growth hormone, and epinephrine
Effects of insulin in carbohydrates metabolism
Promote absorption of glucose in all cells of body except brain, cardiac muscle and kidneys.
Promote muscle glucose uptake: use as energy during moderate or heavy exercise, during the few hours after a meal
Storage of glycogen in muscles (anaerobic energy - glycogen=>lactic acid) and liver
Conversion of excess glucose in FA =>triglycerides=>blood=>stored in adipose tissue
Inhibits gluconeogenesis
Effects of insulin on the liver
Inactivates phosphorylase ( enzyme that splits glycogen into glu)
Enhances uptake of glucose by increase activity of glucokinase (phosphorylation of glucose)
Increase activity of enzymes that promote glycogen synthesis
Depresses the rate of gluconeogenesis (conserves aa in ptn stores)
Promotes conversion of excess of glucose in FA
Effect of insulin on fat metabolism
Increases utilization of glucose by most tissues, which decreases utilization of fat
Promotes FA synthesis:
a) glu=>liver =>Pyruvate=> Acetyl-CoA=>FA=>triglycerides=>blood=>insulin activates lipoprotein lipase in capillary wall of adipose tissue=> triglycerides to FA=>absorbed into adipose cells.
Inhibits action of hormone-sensitive lipase (causes hydrolyses of stored triglycerides )
Promotes transport of glu into fat cells=>glycerol and minute amounts of FA
Consequences of lack of insulin
Increase blood glucose
Increases use of FA for energy in mitochondria=> Acetyl-CoA=>acetoacetic acid (some are converted in beta-hydroxybutyric acid and acetone)
Depresses utilization of acetoacetic acid in peripheral tissues
increase plasma concentration of free FA =>liver converts FA into phospholipids and cholesterol that together with the excess of triglycerides causes atherosclerosis
Effect of insulin on protein metabolism
Stimulates transport of aa into the cells
Increases translation of RNAm
Increases rate of transcription of DNA
Inhibits catabolism of ptn
Depresses rate of gluconeogenesis in the liver (most used substract are plasma aa
