GH1 and Central hypothyroidism: Three patients in the PEG-rhGH group and 1 patient in the daily rhGH group had hypothyroidism during treatment, since it is well known that GH therapy could reveal previously undetected central hypothyroidism (defined by the serum free T4 falling into a subnormal range) and that thyroid function should therefore be monitored when GH therapy starts and whenever there is GH dosage adjustment (22), these patients possibly had undetected central hypothyroidism prior to enrolment.