Inclusion Criteria:

Patients may be included in the study only if they meet all of the following criteria:

1. Adult males and females with GHD, arising during adult life from pituitary ablation or failure, onset of GHD have taken place at least 1 year before entering the study, or,
2. Adult males and females with GHD either idiopathic or secondary to pituitary disease arising in childhood.
3. Demonstrated GHD as documented by a negative response to a standard GH stimulation test within the last 5 years previous year (see Section 3.4.3, part b). Maximal peak must be less than 3.0 ng/ml.
4. Receiving replacement for other deficient hormones for at least 3 months prior to the start of the study, where necessary.
5. Have given informed consent.

Exclusion Criteria:

Patients will be excluded from the study for any of the following reasons:

1. Patients with clinically significant pulmonary, cardiac, hepatic, renal or neuromuscular disease or with chromosomal or genetic malformation syndromes.
2. Patients who have any evidence of an active tumorous process. Intercranial lesions must be inactive and any antitumour therapy must be complete.
3. Pregnant women and lactating females or women who decide to become pregnant during the study and who are not taking adequate contraceptives.
4. Patients thought unlikely to comply with the protocol.
5. Patients taking an investigational drug in the previous month.