Faculty Bibliography

Nine children with Duchenne muscular dystrophy were given Sanorex (mazindol), a growth hormone inhibitor, daily for 6 months. There was no significant change in their muscle function, but there was a significant reduction in weight gain and in levels of growth hormone, somatomedin C, hair zinc, serum zinc, and serum LDH. Selenium and glutathione peroxidase in the serum increased significantly. Thirteen other children with growth hormone deficiency had a significant reduction in hair selenium following growth hormone administration. These results show a significant relationship between growth hormone and selenium nutritional status and confirm our previous reports indicating an effect of growth hormone on zinc nutritional status. It is possible that prolonged therapy with a growth hormone inhibitor would attenuate the course and improve the longevity of patients with muscular dystrophy.

Partial trisomy of the long arm of chromosome 4, usually resulting from a familial segregation of a balanced translocation, has been described in a number of patients. This report describes the genetic and endocrine findings in a 16 year old 46,XY,12q+ mentally retarded male. The banding pattern of the extra chromatin material from this de novo unbalanced translocation shows that the distal segment of the long arm of chromosome 4 is involved. Comparison of the clinical features in this patient with cases of partial trisomy 4q previously reported support the cytogenetic evidence for this translocation involving the distal portion of 4q. Endocrine data suggested an end-organ resistance, characterised by extreme hyperinsulinaemia, primary hypothyroidism, and hypergonadotrophic hypogonadism associated with no signs of autoimmunity. To our knowledge, no endocrine evaluation has been previously reported in patients with partial trisomy 4q.

A pituitary evaluation was carried out in a 12-year-old girl who had early puberty, short stature, optic nerve hypoplasia, and agenesis of the corpus callosum. Her growth hormone (GH) response to insulin-induced hypoglycemia and arginine infusion was blunted. Basal and stimulated levels of prolactin were elevated. The association of GH deficiency and hyperprolactinemia suggests a disruption of the dopaminergic modulation of these hormones. The facial features seen in our patient, such as hypertelorism, V-shaped frontal hairline, and cleft nose and upper lip, are enough to justify the diagnosis of median cleft face (MCF) syndrome. However, the optic nerve hypoplasia and the GH deficiency are characteristics of septo-optic dysplasia, and, to our knowledge, they have never been described in patients with MCF syndrome. Our case fulfills the diagnostic criteria of both, representing a link between both ends of this spectrum.

We have studied the response of blood levels of progesterone, 17-hydroxyprogesterone, 11-deoxycortisol, and cortisol to acute ACTH stimulation in children with isolated GH deficiency. Patients with isolated GH deficiency had generally higher levels of 11-deoxycortisol and lower levels of cortisol than controls both before and after ACTH stimulation. The steroid levels were almost completely restored to control levels after 3 months of treatment with GH. The pre-ACTH treatment levels of 11-deoxycortisol and cortisol were low in patients with both GH and ACTH deficiencies before and during GH therapy. Therefore, GH alone did not appear to have any effect on the hydroxylation of 11-deoxycortisol to cortisol. Before GH therapy, ACTH increased the concentrations of the two steroids. After GH therapy was started, the increase in 11-deoxycortisol was much smaller, but the increase in cortisol was much larger than before therapy. These results suggest a synergistic effect of GH on ACTH action on the biosynthesis of cortisol in the adrenals. Variations in the levels of 11-deoxycortisol and cortisol during hormonal manipulations lead to the identification of the mitochondrial hydroxylation of 11-deoxycortisol as one of the possible sites of action of GH.

13 short children aged 7-13 years who had a retarded bone age and low hair zinc concentration (under 140 micrograms/g) were treated with oral zinc supplements for a year. There was a significant increase in the growth rate in the children whose hair zinc concentration increased. Growth hormone, testosterone and somatomedin C also increased after oral zinc supplementation. Data from 755 short healthy children who have attended our Growth Clinic are presented which describe their hair and serum zinc concentration at different ages. The data indicate a decline in hair zinc concentration after birth with a gradual increase at age 4-6 years, finally reaching adult normal levels after adolescence.

The present study shows that growth hormone administration to 30 growth hormone-deficient children significantly increased their hair zinc concentration (147.0 +/- 31.9 micrograms/ml before, and 168.7 +/- 30.4 micrograms/g after) and decreased their urinary zinc excretion (514 +/- 170 micrograms/g creatine before and 353 +/- 162 micrograms/g creatinine after), suggesting a role for growth hormone in zinc metabolism in children. Since the increase in hair zinc was similar to that found with testosterone on human growth, we speculate that at least some of the anabolic effects of growth hormone and androgens are mediated through their effect on zinc metabolism.

The effects of zinc deficiency and testosterone on fatty acid composition of plasma lipids and microsomes of liver, intestine and testes were studied. The activities of fatty acid desaturase (delta 6 and delta 5) in rat liver and testes were also measured. A significant decrease in the level of arachidonic acid was observed in plasma of normal rats fed the zinc-deficient diet. Castration significantly decreased arachidonic acid but increased 20:3 fatty acid, which is negligible in normal rats. Testosterone and zinc administration restored arachidonic acid to normal values. Zinc deficiency does not significantly change the fatty acid profile in liver, but castration decreased both arachidonic and 22:6 fatty acid. Intestinal mucosal microsomes showed that the predominant fatty acid in this tissue, palmitic acid, is independent of zinc status, whereas polyunsaturated fatty acids 18:2 and 20:4 were decreased by zinc-deficient diet or castration. Zinc deficiency sharply decreased 22:5 fatty acid and to some extent, other polyunsaturated fatty acids in testis microsomes. These changes in fatty acids are in agreement with increased delta 9 desaturation and decreased delta 5 desaturase activity. In testes, both delta 6 and delta 5 desaturase activities are decreased in zinc deficiency. It appears that zinc influences the conversion of linoleic to arachidonic acid, whereas testosterone influences delta 6 desaturase activity. The data suggest that zinc deficiency may be one of the important factors in the causation of polyunsaturated fatty acid deficiency, which, in turn, may induce serum hypertriglyceridemia.

A 14-year-old girl and a 13-year-old boy were found to be growth hormone deficient by insulin-arginine stimulation tests, and were also found to be zinc deficient. When oral zinc replacement was given, they both had a significant increase in growth rate which continued for at least 2 years, and subsequent growth hormone tests were normal.