A 67-year-old retired male went to his doctor, complaining initially ofleg pain that started in his lower back, which then radiated down across the side of his thigh and over the front of his knee. Subsequently, he developed pain that radiated from his back to his front at two different levels: at the chest through the level of his nipples and also at the umbilicus.

His physician performed a history and physical, followed by laboratory tests. He discovered a hard nodule on his prostate and an elevation in several of the blood tests. His PSA (prostate specific antigen), an enzyme secreted by normal prostate tissue (0-4 ng/ml) was 450. Alkaline phosphatase was also elevated at 157 U/L, an indication of bone involvement.

A bone scan was ordered to visualize the bone involvement. (This test uses a calcium analogue attached to a radioactive tag. A special scanner can pick up images of this radioactivity and create an anatomical picture of the skeletal system. The radiation shows up as black spots on the film.)

Usually prostate cancer's growth is initially influenced by the presence of testosterone. If testosterone is removed by castration, the cancer will often shrink for some period of time before the remaining fraction of testosterone-independent cancer cells grow.

This gentleman was not interested in castration and asked if there was another way to treat this. He was treated was a single shot of a drug which is slowly released into the body over a three month time period. Within that time the patient noticed marked relief in his pain.

1. What is the diagnosis of this gentleman?

2. Why would the scan show bone abnormalities?

3. Which endocrine organs are responsible forserum (blood) calcium levels?

4. Describe a mechanism by which a drug could act on the anterior pituitary to lower the testosterone level in the human body.