Effect of Growth Hormone on Lipoprotein Metabolism in Male Pituitary Dwarfs: Changes in Lipoprotein Lipase Activity and Cholesterol Level in HDL Subfractions

To determine the effect of a chronic therapeutic dose (0.24 IU/kg/week) of growth hormone on the cholesterol concentration in serum lipoproteins and postheparin plasma lipase activities in previously untreated children with idiopathic growth hormone deficiency, seven male patients under 10 years of age were studied before and three months after the initiation of growth hormone therapy. Lipase activity was measured by an immunochemical method. The cholesterol concentration in high-density lipoprotein subfractions was determined, using a micromethod for ultracentrifugation. Serum total cholesterol and triglyceride levels did not change significantly during treatment, while the high-density lipoprotein cholesterol level decreased significantly after treatment to 79% of the baseline level, with an equal decrease of cholesterol concentration in both high-density lipoprotein₂ and ₃. Lipoprotein lipase, but not hepatic triglyceride lipase, activity decreased significantly after treatment. These were not associated with changes in either thyroid status as determined by serum triiodothyronine levels or insulin responsiveness after oral glucose challenge, suggesting that these changes may be induced by a direct action of growth hormone.     

Apolipoproteins and Lipoproteins in Children with Type I Diabetes: Relation to Glycosylated Serum Protein and HbA1

ABSTRACT. Serum levels of cholesterol (C), triglycerides (TG), lipoprotein-C and apolipoproteins (apo) A-I, A-II and B were measured in 30 children with type I diabetes mellitus (16 boys, 14 girls, aged 11–14 years) and in 26 healthy controls (15 boys, 11 girls, aged 10–13 years). For 19 diabetics controls matched for age, sex and relative body weight were selected. The diabetic patients were considered to be in fair metabolic control according to HbA₁ levels and glycosylated serum protein concentrations. Mean serum apo A-I, A-II and B, C, TG, low density lipoprotein cholesterol (LDL-C) and high density lipoprotein cholesterol (HDL-C) did not differ significantly between diabetic and nondiabetic children. Very low density lipoprotein cholesterol (VLDL-C) was significantly higher in diabetic children than in controls. Serum C and LDL-C levels showed close univariate linear correlations with glycosylated serum protein (LDL-C: r =0.53, p <0.01, C: r =0.58, p <0.01) in diabetics. The ratio LDL/HDL-C was significantly correlated to HbA₁ levels ( r =0.47, p <0.01). By canonical and multiple linear correlation analysis significant relations of a selected set of variables concerning the control and therapy of diabetes (serum glucose, HbA₁, glycosylated serum protein, insulin dose) with a set of lipoprotein variables (C, TG, VLDL-C, HDL-C, LDL-C, apo A-I, A-II, B) could be demonstrated. From these data we conclude that significant relations between atherogenic serum lipids and lipoproteins (C, LDL-C) and the degree of metabolic control exist in diabetic children, even in the absence of marked dyslipoproteinemia. The close relation of LDL-C and total C with glycosylated serum protein in the diabetics might be due to glycosylation of LDL .     

Effect of Long-Term Treatment with Massive Doses of 1α-Hydroxyvitamin D3 on Calcium-Phosphate Balance in Patients with Vitamin D-Dependent Rickets Type II

Three patients with vitamin D-dependent rickets type II were given massive doses of 1α-hydroxyvitamin D₃ for 29 to 36 months and their calcium-phosphate balance was studied during treatment and one month after cesation of treatment. During treatment fasting hypercalciuria was observed in patient 1 and an increased rate of calcium excretion after calcium loading in patients 1 and 2. In these patients, calcium excretion was parallel with the serum 24, 25-dihydroxyvitamin D. These findings suggested that the responsiveness to 1,25-dihydroxyvitamin D improved during long-term treatment of these two patients with vitamin D-dependent rickets type II.     

Effect of PaCO2 and Haemoglobin Concentration on Day to Day Variation of CBF in Preterm Neonates

Pryds, O. and Greisen, G. (Department of Neonatology, Rigshospitalet, Copenhagen, Denmark). Effect of P_aCO₂ and haemoglobin concentration on day to day variation of CBF in preterm neonates. Acta Paediatr Scand, Suppl 360: 33, 1989.
The CBF was measured on the first three days of life in 22 mechanically ventilated, preterm neonates (mean gestational age 29.5 weeks) with simultaneous recordings of arterial carbon dioxide tension (P_aCO₂), arterial oxygen tension (P_aO₂), haemoglobin concentration (Hgb), haemoglobin oxygen saturation and mean arterial blood pressure (MABP). CBF ± tended to increase slightly with age. The intra-individual variation of CBF ± was positively related to changes in P_aCO₂ (p=0.0004) and inversely related to changes in Hgb (p=0.029). Neither P_aO₂ nor MABP achieved a significant relation to changes in CBF ± Thus, the mean CBF ±-CO₂ reactivity was calculated to 22.1 % per kPa whereas CBF increased by a mean of 11.9% per mM decrease of Hgb thereby providing a constant oxygen delivery to the brain. It is concluded that P_aCO₂ and Hgb have the expected effect on CBF ± in preterm neonates even during respiratory distress shortly after birth.     

Intranasal administration of growth hormone-releasing hormone(1–29)-NH2 in children with growth hormone deficiency: effects on growth hormone secretion and growth

The growth-promoting potential of growth hormone-releasing hormone(1— 29)-NH, (GHRH(1–29)- NH,) in a new formulation for intranasal use was examined in a 6-month pilot study of eight short prepubertal children. The maximal plasma concentration of growth hormone (GH) was below 12 μg/l in two stimulation tests (arginine, insulin), but above 12 (24–90) μg/l after intravenous GHRH, 1 μglkg. GHRH, 50 μg/kg, was insufflated intranasally three times per day over 6 months. On day 1, GHRHinsufflations were followed by distinct GHRH and GH plasma peaks, ranging from 1.2 to 5.4 μg/l and from 10 to 85 mIU/l, respectively. Peak amplitudes were variably reduced after 6 weeks in most patients, and further reduced at 6 months. GHRH antibodies (initially negative) were positive in three patients after 6 weeks. The mean knemometric growth rate rose from 0.24 to 0.48 mm/week after 6 weeks of treatment ( p = 0.03) and then rapidly declined; the mean 6-month stadiometric height velocity did not increase. Local tolerance was good in one patient; most others reported sneezing immediately after insufflation, rhinorrhoea and mild mucosal burning. Treatment was discontinued in two patients after 6 and 12 weeks. It is concluded that intranasal GHRH, though non-invasive, is not suitable in its present form for use in children, because of decreasing absorption and effectiveness with concomitant development of antibodies and local reactions.