Cardiac and Skeletal Muscle Energy Metabolism in Abnormal Growth Hormone States

Growth hormone (GH) is important for growth in childhood, but also has important effects on a number of tissues throughout life. GH deficiency and GH excess (acromegaly, caused by a pituitary tumour) are both cause serious abnormalities of metabolism and long-standing abnormal GH status causes abnormal heart function. In both cases cardiovascular disease is a leading cause of early (premature) death. In the current study we wish to investigate the energy status of the heart in patients with GH excess and deficiency and compare that with age-matched controls. We will perform a blood test to study metabolic parameters. We will perform measurements before treatment, after normalisation of improvement of GH levels and 2 years after start of treatment. Objectives 1. Determine cardiac and skeletal muscle energy metabolism in patients with GH excess (=acromegaly) or GH deficiency and detect changes after normalisation of GH and IGF-1 levels. (IGF-I is a hormone directly influenced by GH) 2. To correlate muscle energy metabolism parameters to GH and IGF-1 status in the control subjects and in both patient groups 3. Determine the prevalence of coronary artery calcifications in patients with GH excess and GH deficiency and correlate this with their metabolic status 4. To correlate coronary artery calcifications to abdominal obesity. Patients will be identified by Endocrinology physicians involved in the study in outpatients clinics or Endocrine wards and they will receive standard care for their disease. Tests related to endocrine hormone abnormalities will be performed as usual clinical practice. The study will involve three 3-hour visits to the Oxford Research Centre and two 1-hour visits to London Scanning Centre. The visits at the Oxford research centre will include Cardiac and skeletal investigations * Standard cardiac MRI will be used to measure right and left ventricular morphology and global function. * 31P Magnetic Resonance Spectroscopy (MRS) to monitor heart mu