Corticotropin and cortisol response to maximal exercise testing in central diabetes insipidus

BACKGROUND: It is known that arginine vasopressin (AVP) has a stimulatory effect on corticotropin (adrenocorticotropic hormone; ACTH) and cortisol secretion especially during stress. The present study was designed to investigate the effect of stress on ACTH and cortisol levels in patients with central diabetes insipidus (DI) with endogenous AVP deficiency receiving AVP therapy, and to determine whether these children need steroid replacement during stress. METHODS: Seven patients with a median age of 12 years (range 7-13 years) with idiopathic central DI on appropriate Desmopressin (DDAVP) therapy (group 1) and seven healthy controls with a median age of 15 years (range 13-20 years; group 2) were included in the study. Acute stress was produced in all children by treadmill exercise, assessed by maximal oxygen consumption and heart rate. ACTH and cortisol levels were determined before and after exercise. RESULTS: In group 1, median ACTH level after exercise (28.3 pg/mL) was not different from the median value (24.0 pg/mL) before exercise. However, median cortisol level (10.5 microg/dL) was significantly increased (14.9 microg/dL; P < 0.05) with exercise. In group 2, cortisol (median 9.3 microg/dL) and ACTH levels (median 6.3 pg/mL) were significantly increased after exercise (15 mug/dL and 13.6 pg/mL, respectively; P < 0.05). There was no significant difference between the groups with respect to cortisol levels before and after exercise, but the stimulated ACTH levels after exercise were higher in patients with DI than in the controls (P < 0.05). A positive correlation was observed between total daily DDAVP dose and cortisol level after exercise (r(s)= 0.786, P < 0.05). CONCLUSIONS: Cortisol response during acute stress is normal in children with DI and these patients do not need extra steroid treatment during stress. In contrast, the normal cortisol response obtained by increased ACTH levels in these patients indicates an increased sensitivity of corticotroph cells.     

Growth and Growth Hormone Secretion in Children Following Treatment of Brain Tumours with Radiotherapy

ABSTRACT. We have studied the growth of 144 children after treatment of brain tumours distant from the hypothalamo-pituitary axis. All had cranial irradiation and 87 spinal irradiation. In 56 patients observed without intervention for 3 years, height SDS in the cranial (CR) group (n= 20) declined from 0.02 to -0.44 and in the craniospinal (CS) group (n= 36) from -0.28 to - 1.11. Failure of spinal growth had a marked effect in the CS group. The onset of puberty was slightly but not significantly advanced; median ages at onset of puberty were 10.3 years in girls and 12.1 years in boys.
Of the total group 86.4% had clinical and biochemical evidence of growth hormone insufficiency. Fifty-two children, 33 (28 CS; 5 CR) of whom were prepubertal, received biosynthetic human growth hormone, in a dose of 15 mU/m²/week by daily injection for a period of one year. Height velocity SDS increased significantly in both groups from -2.74 to + 1.90 (CS) and from -1.0 to +4.26 (CR). Spinal response to GH treatment was restricted in the craniospinal group.