Question
Which of the following is a contraindication to the administration of growth
hormone?
A. The height of the child is under 4 feet
B. The child's age is between 5 and 6
C. The epiphyseal shaft is open
Incorrect
D. The epiphyseal shaft is closed
Correct Answer
Incorrect
Correct Answer: D. The epiphyseal shaft is closed
A closed epiphyseal shaft is a contraindication for administration of growth
hormone. Human growth hormone is produced via the anterior pituitary of the
brain in the acidophilic, somatotrophic cells. Its production is tightly regulated
,through several complex feedback mechanisms in response to stress, exercise,
nutrition, sleep, and growth hormone itself. The primary regulation factors are
growth hormone-releasing hormone (GHRH) produced in the hypothalamus,
somatostatin, produced in various tissues throughout the body, and ghrelin,
which is produced in the gastrointestinal tract. There are no exact height or age
requirements for the administration of growth hormone.
Option A: GHRH functions to promote HGH production and release. Somatostatin
inhibits the release of GHRH as well as the HGH release response to GHRH
stimulus and increases in hypoglycemia. Ghrelin is a hormone produced by the
stomach as part of the hunger response. Functionally, the ghrelin response is
protective against hypoglycemia. When elevated, ghrelin binds to somatotrophs
to stimulate HGH secretion.
Option B: Insulin-like growth factor-1 also acts to inhibit HGH by both directly
inhibiting somatotrophic HGH release and indirectly through synergistically
increasing the release of somatostatin. Additionally, HGH will negatively feedback
into the hypothalamus, thus decreasing GHRH production. The net effect of this
regulatory mechanism produces a pulsatile release of HGH into circulation that
varies hourly.
Option C: In general, HGH levels will be increased in childhood, spike to their
highest levels during puberty, and subsequently decrease with increased age.
HGH has two mechanisms of effect: direct action and indirect action. The direct
effects of HGH on the body are through its action on binding to target cells to
stimulate a response. The indirect effects occur primarily by the action of insulin-
,like growth factor-1, which hepatocytes primarily secrete in response to elevated
HGH binding to surface receptors.
2. Question
Miley has been taking growth hormones for quite some time now. As a recipient
of the agent, she should be aware that a side effect of growth hormone is:
A. Increased tumor growth
Correct Answer
B. Soft tissue hypertrophy
C. Dwarfism
D. Hyperthyroidism
Incorrect
Incorrect
Correct Answer: A. Increased tumor growth
Growth hormone may increase the size of a tumor if one is present. In addition to
the lack of evidence for effectiveness of human growth hormone in these
proposed uses, it causes side effects such as diabetes, carpal tunnel syndrome,
fluid retention, joint and muscle pain, and high blood pressure. Many of these
side effects were seen in studies that used much higher doses of human growth
hormone than are now used in elderly people, so there is hope that studies using
, lower doses alone or in combination with modest doses of anabolic steroids may
show a positive ratio of benefits to side effects. Hypothyroidism and soft tissue
atrophy are the side effects. Dwarfism is the indication for therapy.
Option B: Anabolic-androgenic steroids (AAS) and other hormones such as growth
hormone (GH) and insulin-like growth factor-1 (IGF-1) have been shown to
increase muscle mass in patients suffering from various diseases related to
muscle atrophy.
Option C: Recombinant human growth hormone therapy (rhGH) is an effective
treatment for patients suffering from growth hormone deficiency. Early
intervention can prevent short stature and the psychosocial stress associated with
it.
Option D: Hyperthyroidism is associated with increased serum IGF-I levels and
marked alterations in the neuroregulation of GH secretion. These changes involve
decreased GH responsiveness to GHRH at the pituitary level and, at the
hypothalamic level, a lack of suppressive effect of an oral glucose load.
3. Question
Vasopressin is which of the following pituitary hormones?
A. Antidiuretic hormone
Correct Answer
B. Desmopressin acetate