206
CASE FILES: BIOCHEMISTRY
[22.3]
Which of the following complications is less likely to occur in type II
diabetics, as opposed to type I diabetics?
A. Retinopathy
B. Weight gain
C. Cardiovascular disease
D. Hypoglycemic coma
E. Neuropathy
A nsw ers
[22.1]
C. Of the organs listed, changes in hepatic metabolism are most
likely to affect circulating glucose and lipids. This in turn influences
pancreatic insulin secretion. During type II diabetes mellitus,
increased hepatic glucose output contributes to the observed hyper-
glycemia and subsequent hyperinsulinemia, whereas complex alter-
ations in lipid metabolism contribute to dyslipidemia. In contrast,
changes in metabolic fluxes within the brain, kidney, heart, and
spleen are often a consequence, rather than cause, of their environ-
ment. For example, the heart increases further reliance on fatty acids
as a fuel in the diabetic milieu.
[22.2]
E. The underlying cause of type II diabetes mellitus is insulin resist-
ance (an inability to respond normally to physiological concentra-
tions of insulin). Protein phosphatase 1 is an integral mediator of the
metabolic effects of insulin. Failure to activate protein phosphatase 1
adequately in response to insulin would therefore attenuate the meta-
bolic actions of this hormone. Decreased activity of glucose trans-
porter 1, glycogen phosphorylase, and pyruvate carboxylase would
influence basal glucose transport, glycogenolysis, and gluconeogen-
esis, respectively. Decreased glucagon levels would tend to improve
effectiveness of insulin action.
[22.3]
D. Hypoglycemia is a common complication associated with over sup-
plementation of type I diabetics with insulin. This is less common in
type II diabetics, because insulin therapy generally occurs only in the
later stages of the pathogenesis of this disease. Retinopathy, cardiovas-
cular disease, and neuropathy are common complications associated
with both forms of diabetes mellitus. In contrast to type I diabetics,
type II diabetics tend to be overweight. Whether weight gain is a cause
or consequence of disease progression is under current debate.
previous page 220 Case Files   Biochemistry read online next page 222 Case Files   Biochemistry read online Home Toggle text on/off