IGF-I
GENERATION TEST IN SHORT CHILDREN WITH NORMAL GROWTH HORMONE SECRETION AFTER
TWO PROVOCATIVE TESTS
Zosi P, Karakaidos D, Fotinou A,
Triantafyllidis G, Georgiadis H,
Karis C
Pediatric Department, General Hospital of
Nikea "St. Panteleimon",
Piraeus, Greece
The insulin-like growth factor
IGF-I generation test (GT) can be valuable in the diagnosis of certain types
of growth hormone (GH) disturbances. We performed the IGF-I generation
test in non-growth hormone deficient children, in order to identify other possible causes,
such as growth hormone insensitivity
syndrome, biologically inactive growth hormone and differentiate between GH insensitivity and
neurosecretory disturbance.
Objective:
The
aim of the present study was to assess the value of the IGF-I generation
test after a 4-day administration of rhGH in children with short stature, low
IGF-I and normal GH secretion.
Patients
and method:
Seven
prepubertal children (5 boys and 2 girls) with short statures, height SDS
-2,6¡À0,4,mean height speed velocity SDS - 2,3¡À0,8, chronological age 8,7¡À2,7 years
(age range 3,6-11,8) and bone age 7,3¡À2,5 years with normal thyroid function test
and normal GH secretion after two provocative tests(L-Dopa, clonidine or I.T.T.),
were enrolled in the study. All received human recombinant growth hormone at a
dosage of 0,1 lU/kg of body
weight subcutaneously for 4 days. Blood samples for IGF-I determination were obtained on days 0,1,2,3
and 4. The results are shown on
Table I.:
Table I. IGF-I
generation test after treatment with rhGH
Pretreatment
|
First day
|
Second day
|
Third day
|
Fourth day
|
99,6¡À90,5*
|
177,4¡À98,8*
|
322,5¡À180,*
|
436,6¡À182,4*
|
452,8¡À80,9*
|
*ng/ml
Results:
IGF-I
levels progressively increased during the first four days of GH administration
injection treatment and were significantly different from baseline
(p<0,01). Height velocity increased from 2,3¡À0,8 cm in the year prior to treatment
to 8,5¡À0,3 cm during the first years of GH therapy.
Conclusion:
The
use of the IGF-I generation test as a diagnostic tool in growth disorders
can be beneficial and therefore recommended.