Bone density of lumbar vertebrae (L2 to L4) and the whole body in 29 patients with anorexia nervosa were measured by dual photon absorptiometry, and the results were compared with those of 10 age-matched normal controls. The patients had significantly lower bone mineral density (BMD) in L3 and L2-4 than controls. However, there was no difference in whole-body BMD. L3 and L2-4 BMD was positively correlated with body weight and was negatively correlated with duration of illness and amenorrhea. Patients who had been more active 6 months before the time of the study had significantly higher L3 BMD than the less active patients. Most patients had an abnormally low serum estrogen level, whereas the mean serum levels of thyroid hormone (T3, T4), cortisol, calcitonin, parathyroid hormone and vitamin D were within the normal range. No correlation was found between L3 or L2-4 BMD and the levels of these hormones. These results suggest that severe weight loss, low physical activity, longer duration of amenorrhea and deficiency of estrogen contribute to bone loss in patients with anorexia nervosa, whereas calcium-regulating hormones such as parathyroid hormone, calcitonin and vitamin D are unlikely to be a primary contributor to bone loss.

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Abstract— Thymidine kinase (ATP: thymidine‐5′‐phosphotransferase EC 2.7.1.21) of the supernatant fraction from 6‐day‐old rat brain possessed a pH optimum of 8.0 and required the presence of 5mM‐ATP and 2.5 mM‐MgCl2 for maximum activity. The activity was completely inhibited by addition of 1.8 mM‐TTP. The enzyme activity was lost if the same supernatant fraction was refrozen and thawed. Km was 2.8 × 10−6 M for [6‐3H]thymidine. Following subcellular fractionation of rat brain, the greatest proportion and highest specific activity of thymidine kinase was found in the supernatant fraction. Thymidine kinase activities reached a maximum at 6 days of age and then dropped sharply during maturation. Comparative studies of thymidine kinase activities of cerebrum, cerebellum and the remainder of the brain during growth indicated that the activity in the cerebellum was usually higher than those in the cerebrum and the remainder, and the biggest differences obtained at 6 days after birth corresponded with the peak in cerebellar activity.

Insulin sensitivity was studied using the euglycemic insulin clamp technique in 5 female patients with anorexia nervosa and 4 females with bulimia. The results were compared with those of 15 male patients with non-insulin-dependent diabetes mellitus. Euglycemic insulin clamp is performed for 2 h using the Biostator, during which time insulin was infused at a rate of 0.77 mU kg-1 min-1. Fasting plasma glucose and immunoreactive insulin tended to be lower in patients with anorexia nervosa than in those with bulimia (69.8 +/- 6.7 vs 75.9 +/- 7.7 mg/dl, and 5.9 +/- 2.0 vs 9.8 +/- 3.4 U/ml). The mean metabolic clearance rate (MCR) was 9.2 +/- 3.9 ml kg-1 min-1 for patients with anorexia nervosa, 5.1 +/- 2.2 ml kg-1 min-1 for patients with bulimia, and 3.8 +/- 0.3 ml kg-1 min-1 for patients with diabetes mellitus. However, one anorectic had a significantly high MCR. One anorectic and 3 bulimics had a significantly low MCR. These results suggest that insulin sensitivity varied in patients with anorexia nervosa, whereas it tended to decrease in some patients with bulimia but not to the same degree as in patients with diabetes mellitus.

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