
hypopituitarism: a study of growth
hormone and other endocrine functions.
   pituitary function was evaluated in 25 adults with
evidence of hypopituitarism or enlargement of the sella
turcica.  growth hormone secretory function was measured
by radioimmunoassay of plasma samples taken
before and after insulin-induced hypoglycemia in a standardized
test of growth hormone reserve.  all patients
exhibited significant defects in growth hormone secretion,
as indicated by the failure of this hormone to rise
to normal levels in response to hypoglycemia.  the order
of frequency of hormonal loss was: growth hormone,
gonadotropin, adrenocorticotropic hormone, thyroid
stimulating hormone.  no pattern of deficiency was characteristic
for any particular etiology of hypopituitarism.
one patient with asymptomatic enlargement of the sella
turcica (accidentally discovered) had an isolated loss
of growth hormone secretory capacity.  two patients in
the series demonstrated intrinsic deficiency of thyroid
as well as pituitary secretion, and both had elevated
liters of antithyroid antibodies.  this study represents
the first direct evaluation, by radioimmunoassay of
growth hormone function in a series of hypopituitary
adults.  it demonstrates a remarkably high prevalence
of growth hormone loss, and suggests that the growth
hormone response to hypoglycemia may be one of the
most sensitive tests for the diagnosis of hypopituitarism.
