Effects of estrogen on growth hormone following clonidine stimulation
D. M. Wilson, R. J. Dotson, E. K. Neely, P. Cohen, R. L. Hintz and R. G. Rosenfeld
Department of Pediatrics, Stanford University, Calif.
OBJECTIVE--To test the usefulness of estrogen priming to enhance the growth
hormone (GH) response following stimulation with clonidine hydrochloride in
short children. DESIGN--Randomized and patient series. SETTING--Pediatric
endocrine clinic in a referral center. SUBJECTS--Seventy-three children
(63% male) between 1.8 and 15.4 years of age (mean age, 8.8 years) with
growth problems who underwent clonidine GH stimulation tests were randomly
assigned to receive either estrogen pretreatment or no pretreatment. An
additional 49 subjects, seen before or after the randomized study and who
did not receive conjugated estrogen, are also described. SELECTION
PROCEDURE--Consecutive sample. INTERVENTION--Estrogen pretreatment
consisted of 2.5 mg of conjugated estrogen (Premarin) to be taken the
evening before and the morning of the clonidine GH stimulation test. Growth
hormone concentrations were determined before and 60 and 90 minutes after
the subjects received oral clonidine hydrochloride (5 micrograms/kg) by a
laboratory blinded to the subject's estrogen status. Growth hormone
concentrations greater than 10 micrograms/L were considered normal.
RESULTS--Eight of the 73 subjects failed both clonidine and
arginine-insulin GH stimulation tests. We analyzed the GH data from the 65
GH-sufficient subjects to determine the effect of estrogen pretreatment on
the specificity of the clonidine GH stimulation test. There were no
statistically significant differences in the mean GH concentrations between
the two groups at any time point during the test. CONCLUSIONS--Our data
demonstrate that estrogen priming does not improve the diagnostic yield of
clonidine GH stimulation tests.
