William, a 69-year-old retired male went to his doctor, complaining of leg pain that started in his lower back, ran across the side of his thigh and over the front of his knee. Next, he developed pain that radiated from his back to his front at the chest through the level of his nipples and also at the umbilicus.

A physical and laboratory tests showed 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 453. Alkaline phosphatase was also elevated at 156 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.

William was not interested in castration and asked if there was another form of treatment. He was treated with 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.

a. What is William's diagnosis?

b. Why would the scan show bone abnormalities? What would cause it?

c. Which endocrine organs are responsible for serum calcium levels?

d. Describe the feedback loop between the anterior pituitary and the production of testosterone in the testes. Discuss in brief.