Karl F. Støa

The Effect of the Stimulant Drugs, Dextroamphetamine and Methylphenidate, on Secretion of Growth Hormone in Hyperactive Children.

The stimulant effect of L-dopa (125 to 500 mg) was compared to dextroamphetamine and methylphenidate, 15, and 20 mg, respectively, on growth hormone secretion in 20 hyperactive children. All three stimulants were responsible for peak GH concentration in serum at 60 minutes after drug ingestion; there was no significant difference between the mean GH level at any time of sampling. Seven of the children were retested with L-dopa and dextroamphetamine after six to eight months of treatment with methylphenidate. After treatment, there was a tendency to higher zero time levels of GH, and to delayed and/or paradoxical response to dextroamphetamine. The findings indicate an acute and a probably long-term effect of dextroamphetamine and methylphenidate on the homeostasis of growth hormone. The possible long-term adverse effects of these drugs on the growth of children indicates the need for caution to the widespread use of these agents.

Oestrone sulphatase activity of the rat uterus in different hormonal states.

Oestrone sulphatase activity was determined in 12,500 g supernatant of rat homogenates. The conditions used were 0.5 mM oestrone sulphate and 30 min incubation at pH 8.0 and 37 degrees C. The enzyme activity in uteri from normal animals was found to be 5.1 +/- 0.7 nmol (mg protein)-1 h-1. In ovariectomized and hypophysectomized animals the values were significantly higher, whereas subcutaneous administration of 17 beta-oestradiol to such rats resulted in significantly decreased oestrone sulphatase activities. Progesterone increased the enzyme activity of intact rats. It is concluded that the uterine tissue of rats contains oestrone sulphatase which may be of biological importance and which is inhibited by oestrogen.

Metabolism of oestradiol-17β in the guinea pig

Abstract Glucosiduronates of oestradiol-17β and oestrone were found to be the major urinary metabolites of radioactive oestradiol-17β in guinea pigs. Minor amounts of sulphates of the same two steroids were found. No formation of oestradiol-17α or 16-hydroxylated metabolites was detected. In the male animals oestrone glucosiduronate and oestradiol-17β glucosiduronate were present in the urine in a ratio of about 4:1. In the females this ratio was approx. 1:1.

ENDOCRINOLOGICAL ASPECTS AT FOLLOW‐UP STUDIES IN NEONATAL HYPOGLYCAEMIA

ABSTRACT: Fluge, G., Støa, K. F. and Aarskog, D. (Department of Paediatrics and Hormone Laboratory, University of Bergen, Bergen, Norway). Endocrinological aspects at follow‐up studies in neonatal hypoglycaemia. Acta Paediatr Scand, 64: 280, 1975.–Thirty‐seven cases of neonatal hypoglycaemia were studied at follow‐up at the age of 2 6/12 ‐ 4 9/12 years. Two of them had had hypoglycaemia after the newborn period, and another patient died in a hypoglycaemic state following surgery at 10 weeks of age. Twenty‐three children had oral glucose tolerance tests and intravenous insulin tolerance tests performed. Diabetic glucose tolerance was noted in 3 children. None of them showed symptoms of diabetes mellitus, neither was there any family history of diabetes. One of these patients had experienced hypoglycaemia after the newborn period and responded with hyperinsulinism during the glucose tolerance test. The other hypoglycaemic patient showed an exaggerated insulin release in response to tolbutamide. Deficient serum Cortisol response to insulin‐induced hypoglycaemia was demonstrated in 7 patients and 6 of these had concomitant minimal growth hormone response. One of these patients also had a diabetic glucose tolerance. None were of short stature. It is probable that a disturbance in the hypothalamic‐pituitary‐adrenal axis may contribute to an impaired carbohydrate metabolism in some patients with neonatal hypoglycaemia.

The effect of L-dopa with and without decarboxylase inhibitor on growth hormone secretion in children with short stature.

Abstract The efficiency of L‐dopa alone and L‐dopa plus a dopa‐decarboxylase inhibitor (carbidopa) in provoking growth hormone (GH) secretion was studied in 40 children with short stature. By preventing the extracerebral metabolism, carbidopa increases the availability of L‐dopa to the brain. The study was designed as paired series of growth hormone stimulation tests in which the effect of L‐dopa alone, in different dosage schedules, was compared with the same dose level of L‐dopa plus carbidopa. When L‐dopa was given in full dose (125–500 mg), there was no significant difference in the serum GH concentrations at any time of sampling. In the lower dose level, the stimulant effect of L‐dopa alone tended to be exceeded by the combination of L‐dopa and carbidopa. The serum GH responses to the different schedules indicate that an optimal hypothalamic dopamine concentration for GH release could be achieved with a considerably lower dose of L‐dopa than those employed in previously reported studies. When L‐dopa is combined with a dopa decarboxylase inhibitor, the children have the advantage of less side effects in the form of nausea and vomiting.

Metabolism of Oestradiol-17β by Intestinal Bacteria in Rats

In vitro experiments were carried out in which [4-14C]oestradiol-17beta was incubated with a culture from caecal content from adult male rats at 37 degrees C in an atmosphere of nitrogen. Oestrone was identified as the only certain metabolite. Other metabolites, if present, were quantitatively unimportant. The conversion of oestradiol-17beta to oestrone was estimated to be 22-42%.