Growth hormone replacement therapy in adults for 6 months increased lean body mass, total body water and exercise tolerance, and decreased body fat. Growth hormone replacement for longer than 6 months maintains the advantageous effects seen in shorter-term studies and may have additional effects on body fat distribution, muscle strength and psychological well-being.

The effects of replacement with biosynthetic human GH on carbohydrate tolerance and lipid metabolism were studied in 40 hypopituitary adults during a randomized double blind, placebo-controlled trial for 6 months, followed by a 12-month open trial. The daily GH dose was 0.04 +/- 0.01 IU/kg. Fasting plasma glucose, serum fructosamine, plasmid lipids, lipoproteins, and plasma C-peptide concentrations were measured, and an oral glucose tolerance test was performed every 6 months. There was no change in fasting triglyceride levels at any stage of the study. There was no significant change in fasting total or LDL cholesterol, total HDL cholesterol, high density lipoprotein2 (HDL2) cholesterol, HDL3 cholesterol, apoprotein-A1, or apoprotein-B during GH or placebo treatment in the placebo-controlled 6-months study. In the open phase of the trial, total and low density lipoprotein cholesterol showed a sustained downward trend during GH therapy. Compared to the pretreatment level, the HDL cholesterol concentration was significantly higher at 18 months. Cholesterol subfractions HDL2 and HDL3 and apoprotein-A1 and -B were not different from the pretreatment levels. The total/HDL cholesterol ratio decreased significantly at 12 and 18 months. During the controlled phase, fasting plasma glucose was similar during GH and placebo administration, but fasting insulin and C-peptide increased during GH therapy, but not during placebo treatment. The mean area under the curve (AUC) for glucose increased by a small, but significant, extent over the 6 months of GH treatment and was higher at 6 months than during placebo treatment. The AUC for insulin also increased during GH treatment. During the open trial, the fasting plasma glucose level increased at 6 and 12 months, and the fasting plasma insulin level increased at 6, 12, and 18 months of GH treatment. The plasma glucose AUC during the oral glucose tolerance test was significantly higher at 6 months, and the plasma insulin AUC was significantly higher at 6, 12, and 18 months of GH therapy. In conclusion, GH therapy has some metabolic effects that are considered beneficial and others that are less desirable.

In the present study, a comparison was made of the fatty acid composition of the grey and white matter of the frontal, parietal and parahippocampal regions of post-mortem brains of patients who had died with Alzheimer's disease (n = 15) and control postmortem subjects (n = 10). Diagnosis of Alzheimer-type disease was based on the presence of senile plaques and neurofibrillary tangles in post-mortem sections. Several highly significant and specific differences were observed between the two groups. Adrenic acid (22:4 n-6) was three to four times higher in the grey matter but lower in the white matter in each of the three regions in the Alzheimer brains than in the control group. These alterations were compensated by reciprocal changes in 18:0 in the grey matter and 16:1 fatty acids in the white matter. There was no significant difference in the proportion of other fatty acids, including those of the n-6 and n-3 series, in either the grey or the white matter of any of the three regions of the two groups, except for a higher proportion of 22:6 n-3 in the parietal white matter in the Alzheimer patients. There was no significant relationship between the levels of the individual fatty acids and age at death. It is suggested that the alterations in the fatty acid composition observed in the brains of Alzheimer patients may be caused by an aberration in the system by which essential fatty acids are transported into the brain.

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