Neurophysiology - Metabolism

What will happen when a db/db mouse is parabiosed to an ob/ob mouse?

• Nothing

• db/db looses weight, ob/ob remains obese

• db/db mouse stays the same, ob/ob loses weight

• Both become more obese

• Both lose weight

Answer explanation

db/db mice express satiety factor (leptin) but not the leptin receptor

ob/ob mice do not express the satiety factor (leptin), but DO express the leptin receptor.

db/db will thus express leptin that ob/ob can respond to

What would happen if AgRP neurons were always turned on?

• Increased food intake + increased adiposity

• Increased food intake + no effect on adiposity

• Decreased food intake + decreased adiposity

• Decreased food intake + no effect on adiposity

Answer explanation

AgRP neurons release AgRP, which blocks MC4R (reducing it' activity)

Decreased MC4R activation = increased food take and reduced energy expenditure

If insulin inhibits AgRP, what effects will this have on food intake?

• Increased food intake

• Decreased food intake

• No effect on food intake

You use inhibitory DREADD (hM4Di) to inhibit AgRP neurons, as well as denervate the LEFT fat pad. Where will WAT browning occur?

• Both the left + right fat pads

• No effect on either fat pad

• WAT browning in the left but not the right fat pad

• WAT browning in the right but not the left fat pad

Tanycytes express VEGF in response to low glucose. VEGF acts on blood vessels, causing:

• tight junction disruption, allowing ghrelin into the ARC

• tight junction repair, preventing ghrelin from entering the ARC

Which satiety factors are increased in the FASTED state?

• Ghrelin

• Leptin

• Insulin

Which satiety factors are increased in the FED state?

• Insulin

• Ghrelin

• Leptin

Melanocortin 4 receptor (MC4R) activation is inhibited by:

• AgRP/NPY

• a-MSH

What happens when POMC neurons detect insulin and leptin?

• Decreased food intake

• Increased WAT browning

• Decreased HGP

• Decreased WAT browning

• Increased food intake

What happens when AgRP neurons detect insulin and leptin?

• AgRP neurons become less active

• Food intake increases, EE decreases

• Food intake decreases, EE increases

• AgRP neurons become more active