Growth and Asymmetric diMethylArginine

Inclusion Criteria: * Group A: GHD, defined by 2 GH peaks less than 6.6 ng/ml (20 mU/L) at two stimulation tests * Group B: IUGR, defined by a birth length and/or a birth weight inferior to - 2 SD for gestational age according to Usher and McLean charts * Group C: Control children matched to children matched to subjects of groups A and B, according to gender and age * Informed consent signed by representative of the parental authority Exclusion Criteria: * Chronic disabling disease (ex: diabetes, severe asthma) * Evolving cancer * Severe psychiatric disorder (ex: autism, schizophrenia; severe depression) * Hypothalamic tumor (ex: craniopharyngioma) * Anamnesis of cranial irradiation * Overweight, obesity or thinness * Precocious puberty * Non-replacing therapy by glucocorticoids or sex steroids less than 1 month before the exploration * Anterior treatment by recombinant human GH * Other conditions, treatments or habits impacting arterial reactivity: acrocyanosis, cryoglobulinemia, beta adrenergic blocking habits, tobacco smoking or other drug addictions, dyslipidemia * Pregnancy or lactation * Acute infection less than three weeks before the investigation * Participation to a therapeutic protocol * Impossibility for the representatives of the parental authority to understand the objectives of the protocol * Absence of social security coverage. Refusal by the parents to sign the informed consent or oral refusal by the child to participate to the study