Endocrine Flashcards
why can gigantism therapy lead to hypothyroidism?
somatostatin inhibits both GH and TSH (watch out for hypothyroidism when treating gigantism)
cutting stalk of pituitary stalk causes increase in which hormone levels? not prolactin or oxytocin because?
prolactin and oxytocin will be secreted by hypothalamus at normal levels not increased levels
however, prolactin release is under negative control by dopamine which is produces in hypothalamus and transported to pituitary lactrotroph cells-cutting the stalk removes this inhibition and prolactin levels increase
describe Kimmelstiel-Wilson nodule-structure, location, disease
ovoid, PAS-positive, hyaline masses. found in mesangial core at edge of glomerulus
seen in diabetes glomerulosclerosis
effect of glucagon, Epi, and glucocorticoids on glycogen synthesis?
glucagon and Epi (catabolic) both increase glycogen phosphorylase activity, increasing glycogenolysis
glucagon also inhbits glycogen synthase, promoting glycogenolysis
glucagon works in liver and epi works on muscle and adipose tissue and liver
glucocorticoids (anabolic) act in liver to increase glycogen synthesis and accumulation
Grave’s disease-def, clinical symptoms, levels of rT3, T4 and TSH, and radioactive iodine uptake
thyroid-stimulating immunoglobins results in excessive movement of thyroglobin from colloid into plasma.
- thyroglobin bind iodine and produces thyroxine (T3)
- rT3 and T4 and radioactive iodine uptake are increased
- TSH is decreased
hypothyroidism-clinical features
dry skins, brittle hari, hair loss, weight gain, fatigue, and cold intolerance
Hashimoto disease-def, thyroid gland description, TSH, T4 levels
- autoimmune disorder that leads to hypothyroidism, elevated levels of anti-thyroid peroxidase (TPO) and antithyroglobulin antibodies
- gland is enlarged and uniformly firm (from chronic inflammation)
- elevated TSH and reduced T4 levels
name 2 examples of ketoacids
3-hydroxybutyrate, acetoacetate
acetoacetate:3-hydroxybutyrate ratio
decreases in diabetes and alcoholism because 3-hydrox increases
suspect pseudohypoparathyroidism when? levels of serum ca2+ phosphate, PTH. defined as
mentally retarded child with shorten metacarpals
- low CA2+, high phosphate, high PTH
- due to end-organ insensitivity to PTH, can be caused by decreased expression of Gs in RBCs-leads to decreased cAMP expression
why is Acetly-Coa carboxylase activated by hepatocytes response to insulin? why not increased activity of hexokinase?
Acetyl-CoA carboxylase catalyzes the rate-limiting step in fatty biosynthesis and is activated by insulin
hexokinase is not found in liver cells (glucokinase is) nor is it regulated by insulin. instead glucokinase gene expression is increased with hyperinsulinemia
role of glucokinase when a pt has high insulin serum levels and low glucose levels
mutated glucokinase has a higher affinity for glucose and coverts glucose to glucose-6-phosphate trapping it in the hepatocytes. other cells are unable to utilize glucose (i.e.) pancreas and insulin is up regulated in order to increase uptake of more glucose in blood.
urinary sodium levels in SIADH? why?
serum sodium levels are low b/c of increase water reabsorption. also increase volume inhibits release of renin from kidneys, decreasing action of aldosterone and increase urine sodium
name the hormones released in a cyclic manner- which one depends on suprachiasmatic nucleus
TSH, GH, prolactin (rely on sleep patterns more than light and darkness) and LH (linked to pulsatile manner of GnRH which does not rely on suprchiasmatic nucleus)
ACTH relies on circadian clock
describe three different types of hypothyroidism and effect of TRH injection test on TSH levels
hypothalamic hypothyroidism- slightly increase TSH response, but slower and
pituitary-no response
primary-exaggerated response, TSH levels are already high b/c of low thyroid hormone
diffuse nontoxic goiter has similar histology
multinodular goiter, just not as nodular
thyroid adenoma aka
thyroid (follicular) adenoma
histo-similar to normal thyroid gland, benign colloid follicles
resected b/c could become cancerous
best initial test to perform in order to evaluate thyroid function
TSH levels
if pt has hyperpigmented skin and mucous membranes then which level of adrenocortical insufficiency is it?
hyperpigmentation indicates high levels of ACTH to it’s most likely primary (ie. Addison’s disease) b/c the pit is responding to low levels of cortisol
medullary carcinoma produces what hormone this can be converted to what? what neuroendocrine disorders are they associated with?
calcitonin, can be converted to amyloid
-associated with MEN 2a and MEN 2b
most common type of pituitary adenoma
prolactin, produces galactorrhea