Differential Effects of rhGH vs. rhIGF-1 on Cardiovascular Risk Factors

Insulin-like growth factor-1 (IGF-1) in some circumstances acts as the mediator of the
metabolic effects of growth hormone. However, there is some evidence to suggest that GH and
IGF-1 act differently in some metabolic pathways. We will study the differences between GH
and IGF-1 when provided as therapy for growth hormone deficiency in adults. Specifically we
will be assessing if either medication impacts cardiovascular risk factors and if so do they
impact risk factors differently. Ten adult males ages 18-65 who are growth hormone deficient
on stable medications and with stable MRI findings (in the event of a known pituitary mass)
will be recruited for the study.

Inclusion Criteria:

- Adult male age 25-65 with documented growth hormone deficiency on stable doses x 3
months (at least) of any hormone replacement therapies and with stable MRIs x 2 years
in the setting of a known pituitary mass.

Exclusion Criteria:

- Female gender

- current GH use or GH use within three months of the study

- diabetes

- hypoglycemia

- liver or kidney disease

- use of drugs that could increase GH secretion (i.e. L-dopa)

- alcohol or substance abuse

- use of investigational drugs within four weeks of our study and use of
supraphysiologic doses of steroids within the previous six months.