- A 48-year-old man complaining of impotence sought medicalattention. Over the years, he has experienced increased difficultywith maintaining and, more recently, achieving an erection. Furtherquestioning revealed that his shoe size has increased from a 9-C to11-EEE over the past 5 years, and his dental plate had to bealtered 3 times in 6 years. Recently friends have remarked onchanges in his appearance. The patient also admitted to a tinglingsensation in his fingers and joint pains. On physical examination,he had coarse facial features with a bulbous nose and abeetle-browed look. His hands, feet, and liver were enlarged.Laboratory studies revealed a fasting blood glucose level of 150mg/dl.
      A). Why did the physicianmeasure the plasma GH level? (Hint: What disease does the physiciansuspect this man has?)
      B). The concentration of whatother peptide hormone that is secreted in direct response to GH iscertainly elevated in this patient’s plasma, and where is thatpeptide primarily produced?
      C). What has caused thechanges in the patient’s facial features, hands, feet andliver?
      D). What has caused theneurologic and joint symptoms?
      E). Why is the fasting bloodglucose level elevated, and what changes in the plasma insulinlevel would you expect to find?
      F). What is the most likelycause of the patient’s impotence, and what hormonal abnormalitiesexplain it?
- A 30-year old woman sustained multiple injuries, including askull fracture, in an automobile accident. Although initially in acoma, she gradually regained consciousness. Five days later sheabruptly developed frequent urination and thirst, with a subsequentfluid intake and output of 8L/day. Vital signs were normal. Routineurinalysis was normal; no red blood cells were present. There wasno glucose in her urine. Urine osmolarity was 75 mOsm/kg (i.e verydilute; high water concentration and low solute concentration).After depriving her of water, she continued to excrete 150 ml/hrand urine osmolarity stabilized at 125 mOsm/kg (serum osmolaritywas 325 mOsm/kg --normal is 300 mOsm/kg; and serum sodium was 158mEq/L—normal is about 145-150 mEq/L).
      C). What regulates waterreabsorption and how does it act on its target cells?
      D). How and where is thisregulatory substance synthesized and stored?
      E). What stimuli normallyinfluence the secretion of this substance?
3. A person thathas a diet deficient in iodine begins to experience weight gain,low blood pressure, and an intolerance to cold. The person also hasa goiter (i.e. enlarged thyroid gland).
      A). What causes the weightgain, low blood pressure, and intolerance to cold?
      B). Why does this person havea goiter?
      C). How is iodine typicallyintroduced in the diet?
