Questions: 13. Insulin-like growth factor is produced by what organ? a. Posterior pituitary b. Anterior pituitary c. Hypothalamus d. Liver e. Pancreas

The answer is the fourth one (d): Liver.

Explanation for each option: a. Posterior pituitary: The posterior pituitary gland primarily releases oxytocin and vasopressin (antidiuretic hormone), not insulin-like growth factor. b. Anterior pituitary: The anterior pituitary gland secretes several hormones, including growth hormone (GH), but not insulin-like growth factor. c. Hypothalamus: The hypothalamus produces releasing and inhibiting hormones that regulate the anterior pituitary, but it does not produce insulin-like growth factor. d. Liver: The liver is the primary organ responsible for producing insulin-like growth factor (IGF), particularly IGF-1, in response to stimulation by growth hormone. e. Pancreas: The pancreas produces insulin and other hormones like glucagon, but it does not produce insulin-like growth factor.

Summary: Insulin-like growth factor is produced by the liver.