37 Assessment of Sleep-Associated HGH Secretion in Normal Children and in Endocrine Disorders

Abstract

Bromocriptine (1.25 mg BID) was administered orally to a 23 year old asymptomatic female with accelerated growth and a parasellar tumor (tissue type unknown). Other forms of therapy were refused. Length increased from 76 to 95 cm (22 cm/yr) and weight increased from 10 to 16.25 kg between ages 13 and 23 months. Bone age was 2 years at a chronolorical age of 18 months. Somatomedin C level was 4.3 Ulml (n=2: normal 0.8 to 2.2 Ulml). Thirteen growth hormone values during overnight monitoring averaged 4.7 ng/ml, range 1.8 to 7.9 ng/ml. Suppression to 5.0 nglml was seen during an OGTT. Other neuroendocrine functions were normal. No evidence of isosexual precocity was noted. Somatomedin C levels were 3.2, 2.6, 2.5. 2.4, and 2.2 U/ml on days 1 to 5 of therapy, 2.5 Ulml at 14 days and 2.7 Ulml at 56 days. Length increased from 95 to 97 cm (4.8 cm/ yr) during the first 5 months of therapv. CT scan at 5 months shows no change in tumor size. The patient remains asymptomatic.The decrease in levels of somatomedin C associated with a reduction in the growth rate may have resulted from decreased GH oroduction; however. other effects of bromocriptine, such as blockinr the peripheral action of somatomedins may be involved. In rats permanent stunting follows neonatal head-irradiation (Head-X); during the post-weaning period full catch-up growth (CU) occurs after fasting (F); failure of CU occurs after cortisone treatment (C); and superimposition of F or C on Head-X results in similar responses in the stunting after Head-X. In this study growth hormone (GH) secretory profiles were determined in rats treated with Head-X, F or C. Superior vena cava blood was sampled at 15 min intervals during the light phase in chronically cannulated undisturbed animals. Sampling duration was 9 h in Head-X, 6 h in F, and 12 h in C. The results, ex- EXPEBIYENTAL EVIDEKCE FOR CENTRAL NERVOUS SYSTEFI COKTROLS(13) 98.4t11.9 (16) 84.6~10.9 (7) 55.3C7.4 P <0.025 ~'3.05 ~0.025 Normal pulsatile GH rhythm existed in all three models. The data indicate that GH controls are linked to the CU control. That GH secretion is decreased in Head-X is conpatible with the concept that brain injury has reset growth controls for a smaller body size. We conclude that CH release is linked to the putative CU control through a mechanism which senses the discrepancy between actual body size and normal body size for age.

Growth Hormone Secretion during Sleep

“…This confirms the findings of Finkelstein et al [6] who showed a rise of GH secretion during sleep at the beginning of puberty in a few cases. Bierich et al [1] obtained concordant data in a more recent study. Minuto et al [ 15] evidenced the occurrence of multiple secretory peaks also during waking hours at the beginning of puberty.…”

Serum Growth Hormone Levels in Provocation Tests and During Nocturnal Spontaneous Secretion: a Comparative Study1

“…However, comparing the highest peaks obtained after arginine to those occurring during sleep, it becomes evident that the nocturnal maxima are much higheralmost twice as high as the values after arginine. 3. Maximum peaks attained during arginine provocative tests for hGH in healthy children.…”