The hormone peptide YY is best known for which function?

Peptide YY (PYY) is a hormone produced in the gastrointestinal tract, primarily in response to food intake. Its primary role is to inhibit appetite and reduce food intake. When food is consumed, PYY is released and signals to the brain the sensation of fullness or satiety, thereby helping to regulate energy balance and body weight.

This function is crucial in maintaining homeostasis in the body, as it aids in controlling hunger and prevents overeating. Research has shown that higher levels of PYY are associated with decreased appetite and increased feelings of satiety. Therefore, its role in appetite inhibition is well established and is the most recognized function of this hormone.

The other options do not accurately represent the primary function of PYY. While insulin production and metabolic rate are important aspects of energy balance, they are more closely associated with other hormones such as insulin itself or glucagon. Lactation is primarily regulated by hormones like prolactin and oxytocin, which are separate from the functions of peptide YY.