Endocrine functions in Huntington's disease. A two-and-a-half years follow-up study

An oral glucose tolerance test (OGTT) was performed in 1985 in 10 patients with Huntington's disease (HD), while 10 healthy age-matched volunteers served as controls. Two-and-a-half years later, in 1988, 8 of the original 10 patients were reinvestigated. Apart from glucose, insulin and growth hormone (sampled at 30 min intervals) the following parameters of endocrine function were assessed: C-peptide (at times 0 and 60 min), glycosylated haemoglobin (HbAlc), somatomedin-C, and basal prolactin. In 1985 one female patient was considered to have impaired glucose tolerance, and this same patient, as well as another male patient, had a paradoxical rise in GH secretion. None of the other measurements of endocrine function differed significantly from control. In 1988 the HD patients had clinically deteriorated significantly, as measured by the Shoulson and Fahn Scale. Six of them completed a repeat OGTT. Of these 6, the same female as in 1985 showed impaired glucose tolerance. Now none of the participants had a paradoxical GH rise. The HD patients did not show any deterioration of the parameters of glucose metabolism, nor of GH secretion. The basal prolactin level, however, decreased significantly in these 2.5 years, from 9.3 +/- 3.2 micrograms/l to 6.1 +/- 3.0 micrograms/l (P less than 0.01).