The purposes of the study is to investigate whether circulating levels of ghrelin decreases after an iv injection of GnRH in girls with suspected central premature puberty and to investigate the effects of different post sampling handling on the preservation of acylated ghrelin.
Patients with clinically suspected central premature puberty undergo a GnRH stimulation test to have an appropriate diagnosis. 20 such girls will be recruited to this study and a modified GnRH stimulation test will be done. The modification includes prolonged blood sampling time (0, 30, 60, 90, 120, and 150 min after the GnRH injection instead of the usual 0, 30, 60, and 90 min). The girls will also be investigated twice. In randomised order they will be given either GnRH or placebo (isotone saline), on different days. One week to one month will separate the different investigation days. The proteinase inhibitor 4-(2-aminoethyl) benzene-sulfonyl fluoride hydrochlorid (AEBSF) will be added to some of the blood tubes, and hydrochloric acid will be added to some of the plasma. All plasma samples will be frozen and all analyses will be done at the same time. Acylated ghrelin will be analyzed by Millipore's specific ELISA kit and deacylated ghrelin will be analyzed by Cayman's specific ELISA kit. Anthropometric data as well as pubertal state will be collected. P-glucose, S-insulin, S-follicle stimulating hormone (FSH), S-luteinizing hormone (LH), and S-estradiol will also be analyzed.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
13
Gonadotropin releasing hormone GnRH (Relefact LHRH) iv injection, single dose, 100 micrograms/square meter body surface, maximum dose: 100 microgram.
Sodium chlorid 9 mg/mL will be given as a single iv injection with the same volume as the volume used for the active substance injection.
Department of Paediatrics, Örebro University Hospital
Örebro, Sweden
Ghrelin concentration after GnRH injection and after saline injection
Paired comparison will be done between the acylated ghrelin concentration after GnRH injection and the acylated ghrelin concentration after saline injection. Paired comparison will also be done between deacylated ghrelin concentration after GnRH injection and deacylated ghrelin concentration after saline injection.
Time frame: 30-150 min after iv injections
Deacylated ghrelin concentrations in samples treated with the inhibitor AEBSF, in samples treated with both AEBSF and hydrochloric acid, and in samples not treated with either AEBSF or hydrochloric acid
Concentrations of deacylated ghrelin will be compared between different handling procedures.
Time frame: At baseline
Deacylated ghrelin concentrations in samples treated with the inhibitor AEBSF, in samples treated with both AEBSF and hydrochloric acid, and in samples not treated with either AEBSF or hydrochloric acid
Deacylated ghrelin concentrations will be compared at 150 min after iv injections between different handling procedures.
Time frame: 150 min after iv injections
Acylated ghrelin concentrations in samples treated with and without hydrochloric acid
Acylated ghrelin concentrations will be compared between different handling procedures.
Time frame: 0-150 min after iv injections
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