Term
| The hypothalamus produces _____ and _____ which target the anterior pituitary to release ____ which targets the ______ to produce _____ |
|
Definition
GHRH & somatostatin
GH
liver
IGFs |
|
|
Term
| What effect does GH have on cells? |
|
Definition
promotes movement of AAs into cells, promoting protein synthesis & subsequently, growth of the tissues
promotes lipolysis of adipose tissue |
|
|
Term
True or False
40-50% of the anterior pituitary are focused around secretion of GH |
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Definition
|
|
Term
|
Definition
|
|
Term
| During what time of day is GH secretion greatest? |
|
Definition
|
|
Term
| Describe the daily secretion patterns of growth hormone |
|
Definition
several large pulses during the night, the greatest approx 1 hr after falling asleep
DRAW THE GRAPH - LOOK AT NOTES! |
|
|
Term
| Does GH secretion increase or decrease during fasting? |
|
Definition
|
|
Term
| If AA concentrations in the blood are high, will GH secretion increase or decrease? |
|
Definition
|
|
Term
True or False
During growth spurts, infants will sleep less |
|
Definition
False
they sleep more - growth is associated with sleep |
|
|
Term
| Describe the secretion pattern of GH over the course of a lifetime |
|
Definition
Base levels are highest early in life
Frequency of peaks are greatest during pubescent growth spurt
Declines with age |
|
|
Term
| How is GH transported in the blood |
|
Definition
| primarily bound to GHBP, but can also be free |
|
|
Term
| What factors decrease GH secretion? |
|
Definition
hyperglycemia
glucocorticoids
endocrine disruptors |
|
|
Term
| IGF-1 & 2 are somewhat homologous to what other hormone? |
|
Definition
|
|
Term
| What action of GH is NOT mediated by IGFs? |
|
Definition
| stimulation of lipolysis in adipose tissue |
|
|
Term
| Is IGF-1 free in the blood or bound to transport proteins? |
|
Definition
| bound to proteins (IGF-BP) |
|
|
Term
Why is it difficult to differentiate
between the direct actions of GH and those of IGF-1 |
|
Definition
| GH stimulates release of IGF-1 in many tissues, not just the liver |
|
|
Term
| Which hormone (GH or IGF-1) increases liver glucose release? |
|
Definition
|
|
Term
| Which hormone (GH or IGF-1) increases plasma glucose concentration? |
|
Definition
|
|
Term
| Which hormone (GH or IGF-1) increases tissue sensitivity to insulin? |
|
Definition
|
|
Term
| Which hormone (GH or IGF-1) increases lipolysis in adipocytes? |
|
Definition
|
|
Term
| Which hormone (GH or IGF-1) increases AA uptake & protein synthesis in muscle cells? |
|
Definition
|
|
Term
| When are the two rapid periods of growth in a human's lifetine? |
|
Definition
|
|
Term
|
Definition
|
|
Term
True or False
GH is released throughout a person's lifetime |
|
Definition
|
|
Term
| What effect does GH have on soft tissue? |
|
Definition
| hyperplasia (increased numbers) & hypertrophy (increased size) of soft tissue cells |
|
|
Term
| Bone forming cells are called _____ |
|
Definition
|
|
Term
|
Definition
| calcified ECM formed by crystallization of calcium & phosphate |
|
|
Term
| When Ca & P crystallize to form bone, _____ is produced |
|
Definition
|
|
Term
| To increase bone length, where must bone deposition occur? |
|
Definition
|
|
Term
| To increase bone diameter, here must bone growth occur? |
|
Definition
| around the outer surface of the bone |
|
|
Term
| Describe the process of linear bone growth |
|
Definition
-chondrocytes of epiphyseal plates produce collagen
-old cartilage calcifies as collagen layer thickens
-chondrocytes are degnerated
-osteoblasts move in & lay bone matrix down on top of cartilage base |
|
|
Term
| Collagen-producing cells at epiphyseal plates are called... |
|
Definition
|
|
Term
| Does GH stimulate bone growth directly or indirectly? |
|
Definition
both
directly: stimulates chondrocytes
indirectly: stimulates liver to produce IGF-1 which stimulates chondrocytes & osteoblasts |
|
|
Term
| Insufficient GH in growing animals causes what? |
|
Definition
|
|
Term
| What causes laron-type dwarfism (pygmies)? |
|
Definition
| In growing animals, GH receptor deficiency reduces responsiveness |
|
|
Term
| Acromegaly associated with adults or growing animals or adults? |
|
Definition
|
|
Term
| Is pituitary dwarfism associated with decreased GH production, or reduced sensitivity? |
|
Definition
|
|
Term
| Over production of GH in growing animals can cause.... |
|
Definition
|
|
Term
| What is alopecia? What type animal is it particularly prevalent in? |
|
Definition
underproduction of GH in adult dogs causes thin skin & hair loss
poodles especially! |
|
|
Term
| How is Cushing's syndrome associated with GH? |
|
Definition
| elevated cortisol inhibits GH synthesis |
|
|
Term
|
Definition
progressively thickened bones/joints & skin in adults due to excessive GH production
enlargement of internal organs |
|
|
Term
| Compare oversecretion of GH in adults to in children |
|
Definition
Adults - causes acromegaly
Children - causes gigantism |
|
|
Term
| What are the negative effects associated with treating children with dwarfism ? |
|
Definition
-costly
-glucose intolerance
-pancreatitis
-psychcological issues with height |
|
|
Term
| What can be done to treat dwarfism in children? |
|
Definition
|
|
Term
| Reduced GH in adults can cause... |
|
Definition
|
|
Term
| Why is recombinant HGH used to treat children with short stature? |
|
Definition
GH is only present in the blood stream for brief periods, difficult to harvest from live donors
other option would be to source from cadavers, people don't want that! |
|
|
Term
| What else might you use GH for aside from treating dwarfism? |
|
Definition
-maintain muscle mass in AIDS patients
-bodybuilding / enhancing athletic abilities |
|
|
Term
| What are dwarf / miniature / teacup cats? |
|
Definition
Miniature - selective breeding for small animals
Dwarf - genetic mutation, chondrodysplastic (stops growth at epiphyseal plates) have short legs
Teacup - breed of dwarf cats |
|
|
Term
| What do chihuahuas, min pins, bostons, pomeranies etc. have in common? |
|
Definition
| They all have ateliotic pituitary dwarfism (GH deficiency) |
|
|
Term
| Why do boxers have shortened snouts? |
|
Definition
| they have brachycephalic achondroplasia which reduces growth of the skull bones |
|
|
Term
| What do basset hounds, corgis, bulldogs, daschunds etc have in common? |
|
Definition
| they all have micromelic achondroplasia (shortened legs) |
|
|
Term
| Name a commercial application of GH |
|
Definition
| increasing milk yield in dairy cows |
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