Q: About a patient with a glucagonoma.


Mouse Islet of Langerhans immunostained for Glucagon


Assume that you find a patient with a glucagon-secreting pancreatic tumor (glucagonoma). Which one of the following is most likely to result from hyperglucagonemia?


a)     Decreased lipolysis


b)     Hyperglycemia


c)      Increased muscle protein synthesis.


d)     Increased liver glycolytic rate


e)     Increased glycogenesis


Biochemistry Question CM-21


A 13 year-old patient with Type I diabetes mellitus, home alone,  takes an insulin injection before lunch but then he gets concentrated in a videogame he is playing and does not eat. Approximately 3 hours later, he becomes sweat, shaky and confused. These symptoms have appeared as a consequence of:


a) increased glucagon release from the pancreas


b) decreased glucagon release from the pancreas


c) increased insulin  release from the pancreas


d) decreased insulin release from the pancreas


e) high sugar levels in blood


f) low sugar levels in blood



Q: About Congenital Adrenal Hyperplasia

Question about Hormones (H-07)


Congenital Adrenal Hyperplasia (CAH) occurs as a consequence of genetic deficit of enzymes that participate in the conversion of cholesterol to cortisol. Failure in producing cortisol results in an increase of ACTH secretion and consequently an increased production of androgens and aldosterone disbalance, (most of the cases also show an unability to synthesize aldosterone).  As a result, clinical consequences can be detected in the newborn, from ambiguous genitalia up to salt-losing crisis that threatens the life of the newborn. That is why newborn screening for this disease exists in almost all states. The enzyme deficiency that is most common in CAH is:


a)     11 hydroxylase


b)     17 hydroxylase


c)      21 hydroxylase


d)     Desmolase


e)     HMGCoA reductase


f)       HMGCoA synthase


g)     HMGCoA Lyase


h)    Sterol cyclase



Q: About Epinephrine action



(CM-06) In recent years, Oral Glucose Tolerance Tests have lost support as a diagnostic tool for Diabetes Mellitus. It overdiagnoses diabetes, because a variety of stresses can produce an abnormal response as a consequence of an epinephrine discharge. Even anxiety over venipunctures may generate sufficient epinephrine to produce an abnormal test. Epinephrine induce an elevation in glycemia because this hormone:


a)     inhibits gluconeogenesis and  glycogenesis


b)     inhibits gluconeogenesis and glycogenolysis


c)      inhibits glycogenolysis and glycolysis.


d)     stimulates glycogenolysis and inhibits glycogenesis


e)     stimulates glycogenesis and gluconeogenesis



Q: Hormones, Receptors and Second Messengers



Question H-01


A typical characteristic of hormones that use the second messenger mechanism is that:


a)     they can not pass through the plasma membrane

b)     the receptor is located in the cytosol

c)      the receptor is located in the nucleus

d)     the receptor is not necessary

e)     the receptor binds to the hormone to allow it to enter the cell



      Answer to H-01



Question H-02


Receptors for steroid hormones can be found:


a)     in the plasma membrane

b)     in the cytosol

c)      in the mitochondria

d)     in the ribosomes

e)     in the Golgi apparatus


 Answer to H-02



Question H-03


The binding of insulin to the insulin receptor triggers:


a)     the interaction of the receptor with a protein G

b)     the activation of  adenyl ciclase

c)      the activation of phospholipase C

d)     a decrease of GLUT4 in the plasma membrane

e)     tyrosine kinase activity


      Answer to H-03



Question H-04



Which of the of the following hormones use cAMP as second messenger?


a)     Insulin

b)     Thyroxin

c)      Progesterone

d)     Aldosterone

e)     Glucagon


Answer to H-04



Question H-05


Hormones that act through Phospholipase C activation, in fact are using three second messengers:



a)     cAMP, Diacylglycerol and Ceramide

b)     cAMP, , Ca++ and Diacylglycerol

c)      cAMP , Ca++ and Inositol 1,4,5 triphosphate

d)     cAMP, Diacylglycerol and Inositol 1,4,5 triphosphate

e)     cAMP, Ca++ and ceramide

f)       Ca++, Diacylglycerol and ceramide

g)     Ca++, Diacylglycerol and Inositol 1.4.5 triphosphate

h)    Ca++, Ceramide, Inositol 3,4,5 triphosphate

i)       Ceramide, Diacylglycerol and Inositol 1,4,5 triphosphate.


  Answer to H-05