Growth hormone improves muscle protein metabolism and whole body nitrogen economy in man during a hyponitrogenous diet

Metabolic Fingerprint of Turner Syndrome

Girls with Turner syndrome (TS) are at increased risk of developing insulin resistance and coronary artery disease as a result of hypertension and obesity frequently seen in these patients. On the other hand, it is known that obesity is associated with increased serum levels of branched-chain amino acids (BCAAs: valine; leucine and isoleucine) and aromatic amino acids. The aim of the study is to compare the metabolic fingerprint of girls with TS to the metabolic fingerprint of girls with obesity. Metabolic fingerprinting using an untargeted metabolomic approach was examined in plasma from 46 girls with TS (study group) and 22 age-matched girls with obesity (control group). The mean values of BCAAs, methionine, phenylalanine, lysine, tryptophan, histidine, tyrosine, alanine and ornithine were significantly lower in the study group than in the control (p from 0.0025 to <0.000001). Strong significant correlation between BCAAs, phenylalanine, arginine, tyrosine, glutamic acid, citrulline and alanine, and body mass index expressed as standard deviation score BMI-SDS in the patients with obesity (p from 0.049 to 0.0005) was found. In contrast; there was no correlation between these amino acids and BMI-SDS in the girls with TS. It is suggested that obesity in patients with TS is not associated with altered amino acids metabolism.

Effects of growth hormone on glucose, lipid, and protein metabolism in human subjects

In evolutionary terms, GH and intracellular STAT 5 signaling is a very old regulatory system. Whereas insulin dominates periprandially, GH may be viewed as the primary anabolic hormone during stress and fasting. GH exerts anabolic effects directly and through stimulation of IGF-I, insulin, and free fatty acids (FFA). When subjects are well nourished, the GH-induced stimulation of IGF-I and insulin is important for anabolic storage and growth of lean body mass (LBM), adipose tissue, and glycogen reserves. During fasting and other catabolic states, GH predominantly stimulates the release and oxidation of FFA, which leads to decreased glucose and protein oxidation and preservation of LBM and glycogen stores. The most prominent metabolic effect of GH is a marked increase in lipolysis and FFA levels. In the basal state, the effects of GH on protein metabolism are modest and include increased protein synthesis and decreased breakdown at the whole body level and in muscle together with decreased amino acid degradation/oxidation and decreased hepatic urea formation. During fasting and stress, the effects of GH on protein metabolism become more pronounced; lack of GH during fasting increases protein loss and urea production rates by approximately 50%, with a similar increase in muscle protein breakdown. GH is a counterregulatory hormone that antagonizes the hepatic and peripheral effects of insulin on glucose metabolism via mechanisms involving the concomitant increase in FFA flux and uptake. This ability of GH to induce insulin resistance is significant for the defense against hypoglycemia, for the development of "stress" diabetes during fasting and inflammatory illness, and perhaps for the "Dawn" phenomenon (the increase in insulin requirements in the early morning hours). Adult patients with GH deficiency are insulin resistant-probably related to increased adiposity, reduced LBM, and impaired physical performance-which temporarily worsens when GH treatment is initiated. Conversely, despite increased LBM and decreased fat mass, patients with acromegaly are consistently insulin resistant and become more sensitive after appropriate treatment.

Altered nutrition state in the severe multiple trauma patients undergoing adjuvant recombinant human growth hormone nutritional support therapy

In order to observe the nutrition state in the severe multiple trauma patients undergoing adjuvant recombinant human growth hormone (rhGH) nutritional support therapy, 45 patients with severe multiple traumas (ISS>25) were randomly divided into 3 groups. All the 3 groups had been supplied with nitrogen and caloricity according to the need of patients for 16 days. The rhGH therapy started 48 h after surgery and lasted for 14 days in two rhGH-treated groups in which rhGH was 0.2 and 0.4 U/(kg . d) respectively, and the resting group served as control one. The levels of nitrogen balance, prealbumin and safety variables (blood sugar, Na+, TT3 and TT4) were observed and compared among the three groups. The levels of nitrogen balance on the postoperative day (POD) 3 and 5 in the rhGH-treated groups were -1.28+/-3.19, 5.45+/-2.00 and -0.18+/-2.55, 6.11+/-1.60, respectively, which were significantly higher than those in the control group (-5.17+/-1.68 and -1.08+/-3.31, P<0.01). The values of prealbumin on the POD 3 and 5 in the rhGH-treated groups were 180.19+/-27.15, 194.44+/-50.82 and 194.94+/-29.65, 194.11+/-16.17, respectively, which were significantly higher than those in the control group (117.42+/-19.10 and 135.63+/-28.31, P<0.01). There was no significant difference between the rhGH 0.2 U/(kg . d) group and rhGH 0.4 U/(kg . d) group in both of the levels of nitrogen balance and prealbumin. It is concluded that the nutritional support therapy with adjuvant rhGH which starts 48 h after surgery improves the nutrition state of the patients with severe multiple trauma. It is safe for severe multiple trauma patients who accept rhGH at the dose of 0.2 and 0.4 U/(kg . d).

Growth hormone effects on protein metabolism

Growth hormone (GH) has a pivotal role in regulating in vivo protein metabolism. GH enhances protein anabolism at the wholebody level, mainly by stimulating protein synthesis. It remains incompletely understood whether this important GH effect on protein synthesis occurs in all tissues. This effect of GH may be different with acute versus chronic administration. These differences in the GH exposure may have different effects based not only on direct GH stimulation of protein synthesis but also the variable effects at the level of gene transcription that ultimately affect protein metabolism. Other GH effects are likely to be mediated by changes in various metabolites and hormones that also likely differ based on the duration of GH administration.

Effects of growth hormone on lipid metabolism in humans

The most immediate effect of growth hormone (GH) administration in humans is a significant increase in free fatty acids after 1-2 h, reflecting stimulation of lipolysis and ketogenesis. This stimulation represents an important physiological adaptation to stress and fasting. When the capacity of GH to increase lipolysis is blocked, the protein-retaining and insulin-antagonistic effects of GH on glucose metabolism are either abolished or weakened dramatically, compatible with a key role for lipolysis in orchestrating the metabolic actions of GH.

Effects of GH on protein metabolism during dietary restriction in man

The metabolic response to dietary restriction involves a series of hormonal and metabolic adaptations leading to protein conservation. An increase in the serum level of growth hormone (GH) during fasting has been well substantiated. GH has potent protein anabolic actions, as evidenced by a significant decrease in lean body mass and muscle mass in chronic GH deficiency, and vice versa in patients with acromegaly. The present review outlines current knowledge about the role of GH in the metabolic response to fasting, with particular reference to the effects on protein metabolism. Physiological bursts of GH secretion seem to be of seminal importance for the regulation of protein conservation during fasting. Apart from the possible direct effects of GH on protein dynamics, a number of additional anabolic agents, such as insulin, insulin-like growth factor-I, and free fatty acids (FFAs), are activated. Taken together the effects of GH on protein metabolism seem to include both stimulation of protein synthesis and inhibition of breakdown, depending on the nature of GH administration, which tissues are being studied, and on the physiological conditions of the subjects.

The protein-retaining effects of growth hormone during fasting involve inhibition of muscle-protein breakdown

The metabolic response to fasting involves a series of hormonal and metabolic adaptations leading to protein conservation. An increase in the serum level of growth hormone (GH) during fasting has been well substantiated. The present study was designed to test the hypothesis that GH may be a principal mediator of protein conservation during fasting and to assess the underlying mechanisms. Eight normal subjects were examined on four occasions: 1) in the basal postabsorptive state (basal), 2) after 40 h of fasting (fast), 3) after 40 h of fasting with somatostatin suppression of GH (fast-GH), and 4) after 40 h of fasting with suppression of GH and exogenous GH replacement (fast+GH). The two somatostatin experiments were identical in terms of hormone replacement (except for GH), meaning that somatostatin, insulin, glucagon and GH were administered for 28 h; during the last 4 h, substrate metabolism was investigated. Compared with the GH administration protocol, IGF-I and free IGF-I decreased 35 and 70%, respectively, during fasting without GH. Urinary urea excretion and serum urea increased when participants fasted without GH (urea excretion: basal 392 +/- 44, fast 440 +/- 32, fast-GH 609 +/- 76, and fast+GH 408 +/- 36 mmol/24 h, P < 0.05; serum urea: basal 4.6 +/- 0.1, fast 6.2 +/- 0.1, fast-GH 7.0 +/- 0.2, and fast+GH 4.3 +/- 0.2 mmol/1, P < 0.01). There was a net release of phenylalanine across the forearm, and the negative phenylalanine balance was higher during fasting with GH suppression (balance: basal 9 +/- 3, fast 15 +/- 6, fast-GH 17 +/- 4, and fast+GH 11 +/- 5 nmol/min, P < 0.05). Muscle-protein breakdown was increased among participants who fasted without GH (phenylalanine rate of appearance: basal 17 +/- 4, fast 26 +/- 9, fast-GH 33 +/- 7, fast+GH 25 +/- 6 nmol/min, P < 0.05). Levels of free fatty acids and oxidation of lipid decreased during fasting without GH (P < 0.01). In summary, we find that suppression of GH during fasting leads to a 50% increase in urea-nitrogen excretion, together with an increased net release and appearance rate of phenylalanine across the forearm. These results demonstrate that GH-possibly by maintenance of circulating concentrations of free IGF-I--is a decisive component of protein conservation during fasting and provide evidence that the underlying mechanism involves a decrease in muscle protein breakdown.

Effects of growth hormone administration on protein dynamics and substrate metabolism during 4 weeks of dietary restriction in obese women

OBJECTIVE

Treatment of obesity with very low calorie diet (VLCD) is complicated by protein loss. We evaluated the effects of coadministration of GH on protein turnover, substrate metabolism, and body composition in VLCD treated obesity.

DESIGN AND PATIENTS

Fifteen obese women underwent 4 weeks of very low calorie diet (VLCD) in parallel with GH treatment (n = 7) or placebo (n = 8).

MEASUREMENTS

Protein metabolism and total glucose turnover were isotopically assayed. Plasma concentrations of amino acids were determined by an HPLC system. Estimated rates of lipid and glucose oxidation were obtained by indirect calorimetry. Fat free mass was determined by DEXA-scan.

RESULTS

Protein breakdown decreased in both groups (tyrosine flux micromol/h): -12% +/- 3 (GH) vs. - 9% +/- 3 (placebo)). Phenylalanine degradation in relation to phenylalanine concentration decreased by 9% in the GH group, whereas an increase of 8% was observed in the placebo group (P = 0.1). Plasma concentrations of several amino acids were significantly decreased in the placebo group, while urea excretion decreased in the GH group. A decrease in FFM was found in placebo treated patients (2.14% +/- 1.9 (GH) vs. - 3.54% +/- 1.6 (placebo), P < 0.05). Rates of lipid oxidation tended to be increased by GH treatment (lipid oxidation (mg/minutes): 79.7 +/- 5.9 (GH) vs. 64.6 +/- 5.9 (placebo), P = 0.1).

CONCLUSION

During dietary restriction GH primarily seems to conserve protein by a reduced hepatic degradation of amino acids.

Perioperative growth hormone treatment and functional outcome after major abdominal surgery: a randomized, double-blind, controlled study

OBJECTIVE

To evaluate short- and long-term effects of perioperative human growth hormone (hGH) treatment on physical performance and fatigue in younger patients undergoing a major abdominal operation in a normal postoperative regimen with oral nutrition.

SUMMARY BACKGROUND DATA

Muscle wasting and functional impairment follow major abdominal surgery.

METHODS

Twenty-four patients with ulcerative colitis undergoing ileoanal J-pouch surgery were randomized to hGH (12 IU/day) or placebo treatment from 2 days before to 7 days after surgery. Measurements were performed 2 days before and 10, 30, and 90 days after surgery.

RESULTS

The total muscle strength of four limb muscle groups was reduced by 7.6% in the hGH group and by 17.1% in the placebo group at postoperative day 10 compared with baseline values. There was also a significant difference between treatment groups in total muscle strength at day 30, and at the 90-day follow-up total muscle strength was equal to baseline values in the hGH group, but still significantly 5.9% below in the placebo group. The work capacity decreased by approximately 20% at day 10 after surgery, with no significant difference between treatment groups. Both groups were equally fatigued at day 10 after surgery, but at day 30 and 90 the hGH patients were less fatigued than the placebo patients. During the treatment period, patients receiving hGH had reduced loss of limb lean tissue mass, and 3 months after surgery the hGH patients had regained more lean tissue mass than placebo patients.

CONCLUSIONS

Perioperative hGH treatment of younger patients undergoing major abdominal surgery preserved limb lean tissue mass, increased postoperative muscular strength, and reduced long-term postoperative fatigue.

Albumin synthesis and bone collagen formation in human immunodeficiency virus-positive subjects: differential effects of growth hormone administration

Loss of lean tissue often accompanies human immunodeficiency virus (HIV) infection. Exogenous human recombinant GH (hrGH) has been shown to be beneficial in reversing this wasting. However, catabolic effects of hrGH on muscle protein metabolism have also been reported. Therefore, the responsiveness of other GH-sensitive tissues, including bone formation and albumin synthesis, has been examined. Anabolic activity in bone, from serum levels of carboxy-terminal propeptide of type I collagen, was stimulated by 2 weeks of hrGH in controls (56 +/- 15%, P = 0.002), patients with asymptomatic HIV (24 +/- 10%, not significant), patients with AIDS (47 +/- 7%, P < 0.001), and patients with AIDS and > 10% weight loss (21 +/- 12%, P = 0.02). Albumin synthesis, determined from the incorporation of L-[2H5]phenylalanine, was increased in response to hrGH in controls (23 +/- 7%, P < 0.05), HIV+ subjects (39 +/- 16%, P < 0.05), and patients with AIDS (25 +/- 7%, P < 0.01). Patients with AIDS and weight loss, however, did not increase albumin synthesis (-0.6 +/- 12%) in response to hrGH. The results indicate variable anabolic responses to hrGH. Bone collagen synthesis remained sensitive to hrGH, whereas, the anabolic action of hrGH on the synthesis of albumin diminished with severity of disease. However unlike muscle protein synthesis, albumin synthesis was not depressed below basal levels by hrGH.

Responsiveness of muscle protein synthesis to growth hormone administration in HIV-infected individuals declines with severity of disease

This study was undertaken to determine if human recombinant growth hormone (hrGH, 6 mg/d for 2 wk) would stimulate muscle protein synthesis in AIDS wasting. Healthy controls were compared with patients who were HIV+, had AIDS without weight loss, and had AIDS with > 10% weight loss. Before hrGH, rates of skeletal muscle protein synthesis, measured with l-[2H5]phenylalanine, were the same in controls and in all stages of disease. Rates of myofibrillar protein degradation, however, assessed from urinary excretion of 3-methyl histidine, were higher in AIDS and AIDS wasting than in HIV+ or healthy individuals. The group with weight loss had significantly higher TNFalpha levels but not higher HIV viral loads. Muscle function, as determined by isokinetic knee extension and shoulder flexion, was significantly higher in controls than all infected individuals. After GH, rates of protein synthesis were stimulated 27% in controls, with a smaller increase (11%) in HIV+, and a significant depression (42%) in AIDS with weight loss, despite fourfold elevation in insulin-like growth factor-I in all groups. There was a significant correlation of hrGH-induced changes in muscle protein synthesis with severity of disease (P = 0.002). The results indicate increased basal muscle protein degradation and decreased responsiveness of muscle protein synthesis to GH in the later stages of disease.

Growth hormone modulates amino acid oxidation in the surgical patient: leucine kinetics during the fasted and fed state using moderate nitrogenous and caloric diet and recombinant human growth hormone

Twelve patients (aged 70 +/- 9 years) who were scheduled for resection of rectosigmoid colon adenocarcinoma but were otherwise healthy were randomly allocated after surgery to receive either peripheral parenteral nutrition alone ([PPN] n = 6) or in combination with recombinant human growth hormone (rGH) at a daily dose of 0.15 U x kg(-1) x d(-1)(PPN + rGH, n = 6). The daily nutritional regimen was 0.1 g nitrogen x kg(-1) x d(-1) and 20 kcal x kg(-1) x d(-1) (nonprotein energy was supplied as 60% lipid and 40% carbohydrate), and it was maintained for 6 days before and 6 days after surgery. Protein kinetics were studied in all 12 patients during the fasted and fed states before and 6 days after surgery using an 8-hour 13C-leucine tracer infusion. Daily urinary nitrogen, gaseous exchange, and plasma insulin, growth hormone, and insulin-like growth factor-I (IGF-I) were determined before and after surgery. Surgery was responsible for significant increases in postabsorptive whole-body protein flux and synthesis and leucine oxidation (P < .01). Supplementation of PPN with rGH contributed to a significant attenuation of the postoperative increase in leucine oxidation (P = .02), with a significant increase in whole-body protein synthesis (P = .02) and no effect on protein breakdown (P = .40). During the fed state, leucine oxidation increased significantly (P = .005), with the greatest change occurring in the PPN group. Feeding was associated with a significant decrease in whole-body protein breakdown before and after surgery in both groups (P = .001). Postoperative urinary nitrogen excretion was lower but was not statistically significant in the PPN + rGH group compared with the PPN group. There was a significant increase in oxygen consumption (VO2) and carbon dioxide production (VCO2) as a result of feeding and surgery (P < .01). Supplementation with rGH caused a decrease in the respiratory quotient (RQ) (P = .04), particularly after surgery, indicating a direct effect of rGH on fatty acid oxidation. Circulating plasma insulin increased significantly in both groups with feeding and rGH supplementation (P < .05). This was enhanced after surgery, particularly in the rGH group (P < .05). Plasma growth hormone decreased after surgery in the PPN group (P < .05), but did not change as a result of feeding. The circulating levels increased in the PPN + rGH group following subcutaneous administration before or after surgery. Plasma IGF-I decreased after surgery in the PPN group (P < .05), and no changes occurred in the PPN + rGH group with feeding. The present findings suggest a distinct positive effect of rGH on protein synthesis in catabolic patients receiving a moderate intake of nitrogen and calories. This is achieved by modulation of amino acid oxidation. The acute effect of intravenous (IV) nutrients on protein metabolism during the catabolic phase of surgical stress caused a direct decrease in protein breakdown with no effect on protein synthesis.

[Malnutrition and HIV infection]

The wasting syndrome is well known in HIV infected patients. Predominant free fatty mass deletion is achieved. The weight loss results from decrease of food intake, from gut disorders due to HIV or opportunistic infections. Metabolic disorders are reported too. Breakdown of carbohydrates and proteins presents energy source. Raised free fatty acid turn over and hypertriglyceridemia are reported. Polyunsatured fatty acid level is raised inducing free radicals increase. Free radicals delete immune functions (apoptosis). Vitamin and trace element decrease worsen negative effects of free radicals.

Effect of recombinant human growth hormone on the intestinal structure of rats receiving bowel resection and parenteral nutrition

Recombinant human growth hormone (rHGH) can improve nitrogen balance and promotecell proliferation. Little is known about the relationship between rHGH and gastrointestinal mucosal structure and function after bowel resection and parenteral nutrition (PN). The aim of this study was to determine the effect of rHGH on bowel mucosal structure and barrier function in rats receiving 50% small intestinal resection and PN. Thirty Wistar rats with central vein catheterization plus 50% small bowel resection were divided into three groups: chow (chow), standard (STD) and rHGH (rHGH). The chow group received chow food; the STD group was given standard PN; the rHGH group received standard PN plus rHGH (4.8 mg/kg/day, subcutaneously). The groups were maintained on their respective diets for 8 days and then killed. Body weight, small intestinal mucosal thickness, villus height and Goblet cells in the villus were measured. Body weight loss in the STD group was significantly greater than that in the chow and rHGH groups (P< 0.01). The mucosal thickness and villus height of rHGH group were significantly greater than the STD and chow groups (mucosal thickness: 806 +/- 5.5 vs. 533 +/- 6.0 and 593 +/- 6.0 microm; Villus height: 506 +/- 6.0 vs. 295 +/- 5.5 gm and 400 +/- 6.7 lam, respectively) (P< 0.05). The number of Goblet cells in the STD group was significantly greater than the rHGH and chow groups (9.06 +/- 1.07 vs. 5.35 +/- 1.48 and 6.10 +/- 1.51/per villus) (P < 0.01). rHGH can maintain body weight and promote bowel mucosal cell growth and might improve the barrier function of the bowel in rats after 50% small intestinal resection and PN.

Effects of human growth hormone in critically ill nonseptic patients: results from a prospective, randomized, placebo-controlled trial

OBJECTIVES

To study the effects of growth hormone administration on insulin-like growth factor I concentration, nitrogen balance, and fuel utilization, and to study its safety in critically ill nonseptic patients.

DESIGN

Prospective, randomized, placebo-controlled trial.

SETTING

Medical intensive care unit of a university hospital.

PATIENTS

Eighteen critically ill nonseptic patients were studied for 8 days after admission.

INTERVENTIONS

Growth hormone (0.1 mg/kg/day) or placebo was administered as a continuous intravenous infusion on the second, third, and fourth days after admission. The study period was 8 days.

MEASUREMENTS AND MAIN RESULTS

Plasma hormone concentrations were measured every 6 hrs and average daily values were calculated. The 24-hr urinary nitrogen and 3-methylhistidine excretion were measured. Indirect calorimetry was used to calculate fuel utilization. Insulin-like growth factor I concentrations increased in the treatment group from subnormal to normal values and remained increased despite discontinuation of growth hormone treatment (p = .02). Nitrogen balance differed between the groups upon admission: growth hormone group (3.9 +/- 4.1 g/day) vs. controls (13.8 +/- 5.4 g/day), but improved with growth hormone. This finding appeared independent of the imbalance between the groups. The 3-methylhistidine excretion was not different between the groups and did not change during growth hormone administration. Free fatty acids and glycerol concentrations increased during growth hormone treatment, but calculated fuel utilization did not change. During growth hormone treatment, insulin concentrations increased, due to the increased administration of insulin necessary for glycemic control. Side effects other than hyperglycemia were not observed.

CONCLUSIONS

Growth hormone administration in a heterogeneous group of critically ill nonseptic patients resulted in normalization of insulin-like growth factor I levels, even after cessation of growth hormone treatment. Nitrogen balance improved, but this change was transient. Hence, growth hormone affects nitrogen balance, probably partly independent of insulin-like growth factor I.

Adjuvant recombinant human growth hormone normalizes plasma amino acids in parenterally fed trauma patients

BACKGROUND

The addition of an anabolic stimulant during intensive nutrition therapy in trauma patients seems to be a reasonable adjuvant for minimizing muscle-mass erosion. The plasma free amino acid pattern is the mirror of the net amino acid metabolism, and we have measured the progressive changes resulting from recombinant human growth hormone therapy in trauma victims during nutritional repletion in the early catabolic flow phase of injury.

METHODS

In 20 severely injured (injury severity scale = 31 +/- 2), highly catabolic, and hypermetabolic adult multiple-trauma patients, we have measured the fasting (day 0) plasma amino acid levels (48 to 60 hours after injury before starting the nutrition therapy) and their progressive changes during 7 days of IV nutrition support (total parenteral nutrition, 1.1 x resting energy expenditure calories, 250 mg of nitrogen per kilogram per day) with or without adjuvant recombinant human growth hormone. Group H (n = 10) randomly received daily recombinant human growth hormone (0.15 mg of Somatropin per kilogram per day) and Group C (n = 10) received the vehicle of infusion.

RESULTS

Hypoaminoacidemia of trauma is normalized by infusion of recombinant human growth hormone, which indicates its anabolic nature, and this is confirmed in the cumulative nitrogen balance (-281 +/- 139 mg of nitrogen per kilogram per 7 days compared with -809 +/- 151 mg of nitrogen per kilogram per 7 days without recombinant human growth hormone; p < or = .005). This improved nitrogen retention is also reflected in the significantly low blood urea nitrogen levels in the recombinant human growth hormone group, which represents the efficient utilization of the infused amino acids for synthesis of proteins. Elevated plasma insulin-like growth factor-1 levels in Group H compared with those in Group C may also account for this altered amino acid metabolism.

CONCLUSIONS

Recombinant human growth hormone treatment in combination with conventional total parenteral nutrition in the immediate posttraumatic period improved nitrogen metabolism and normalized the plasma free amino acid levels.

[Role of anabolic hormonal factors in surgery in adults]

Hormonal agents with anabolic effect are virtually able to limit or even to counteract the adverse effects of stress and to act in synergy with nutritional support. Hormones with a high theoretic anabolic power include recombinant human growth hormone (rGH), insulin, insulin-like growth factor and testosterone. Other molecules favour anabolism in modifying the catabolic effect of diseases (anti-cytokines, beta-adrenoceptor agonists), in promoting intestinal absorption of substrates or in stimulating epithelial growth (EGF). The results of preliminary studies cannot be transferred into routine clinical practice. The rGH favours the preservation of body mass integrity and various functions. Therefore it could improve postoperative outcome and decrease the duration of hospital stay. A study in severely burnt children showed the metabolic benefits of rGH as well as a shortening of hospital stay because of a decrease of cicatrisation delay after skin grafting. Finally it demonstrated that rGH allows major financial savings in severe burns. The IGF-1 stimulates host defences and decreases the rate of wound infections. The rGH potentiates nitrogen sparing effect of IGF-1 and decreases hypoglycaemia induced by IGF-1. However a study on patients in stress is yet lacking. A combination of growth factors could be virtually efficient, however the cost seems exorbitant. An unquestionable evidence of their clinical efficiency is required before a clinical use in routine can be considered. The postoperative protein catabolism could be decreased by nandrolone decanoate or its derivatives. On the other hand, it has not been proven that protein synthesis, the muscle function or clinical prognosis can be improved by such a treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Muscle function and origin of pain in fibromyalgia

It may be concluded that both peripheral and central mechanisms may operate in the pathophysiology of both impaired muscle function and pain in FM. These mechanisms may in part be attributable to physical deconditioning and disuse of muscle secondary to the characteristic pain and fatigue so often seen in FM. Most likely the initiation of this condition is multifactorial and the combination of peripheral and central factors that constitute a vicious circle may perpetuate the condition into a chronic state.

Growth hormone suppression and glutamine flux associated with cardiac surgery

Pharmacological doses of growth hormone (GH) in humans and rats increase plasma and muscle glutamine values. As major surgery results in a physiological rise in serum GH concentration, we investigated whether this physiological increase in GH altered glutamine metabolism. Eighteen patients undergoing coronary artery bypass graft (CABG) surgery were randomly assigned to receive somatostatin, 100 micrograms subcutaneously at induction of anaesthesia and 8 hourly for 48 h, or placebo. Somatostatin effectively blocked the physiological surge of GH following injury but did not affect plasma or muscle glutamine concentrations, which fell significantly in both groups. Plasma glutamine decreased by 31% (P < 0.01) and 28% (P < 0.01) in the control and somatostatin groups respectively. Muscle glutamine was reduced 45% (P < 0.001) in the control group and 50% (P < 0.001) in the somatostatin group. There was no difference in muscle or circulating glutamate, alanine or branched chain amino acid concentrations or in metabolite values between the somatostatin-treated patients and the control group. There was no relationship between the GH response to surgery and glutamine metabolism following major surgery.

Growth hormone therapy in the elderly: implications for the aging brain

Growth hormone (GH) secretion declines during normal aging, resulting in lower serum insulin-like growth factor (IGF)-I levels. It has been proposed that many of the catabolic changes seen in normal aging, including osteoporosis and muscle atrophy, are in part caused by the decreased action of the GH-IGF-I axis. In addition, patients with GH deficiency have increased overall cardiovascular mortality. Several investigators have initiated GH treatment for elderly patients with relative hyposomatotropinemia. Initial reports suggest that GH can increase muscle mass, improve exercise tolerance, increase REM sleep and cause an enhanced sense of well-being. The basis for neuropsychiatric changes during GH therapy may be due to a direct CNS action of GH itself, to the increased IGF-I secretion which GH elicits, or to enhanced functioning of peripheral organ systems. Long-term studies will determine whether GH or IGF-I can exert a neurotrophic action in the aging brain.

Biosynthetic human growth hormone preserves both muscle protein synthesis and the decrease in muscle-free glutamine, and improves whole-body nitrogen economy after operation

As a reproducible human trauma model, patients (n = 17) undergoing elective cholecystectomy were studied for 3 postoperative days. They were randomly allocated to receive either recombinant human growth hormone (hGH; 0.3 U/kg/24 hours) or placebo together with total parenteral nutrition, including 0.2 gN/kg/24 hours and 135 kJ/kg/24 hours. Before operation and on the third postoperative day, percutaneous muscle biopsies were performed to determine the concentration and size distribution of ribosomes and the free amino acid concentrations. The significant postoperative decrease in the total ribosome concentration (15.3 +/- 6.4%) and the polyribosome concentration (20.9 +/- 6.5%) in the control group was impeded in the group receiving synthetic hGH. Muscle free glutamine decreased by 35.6 +/- 4.2% in the control group and to a lesser extent in the group that was given hGH after operation (p less than 0.05). The protein content of skeletal muscle was unchanged. The cumulated nitrogen balance for the study period was negative in the control group (-7.09 +/- 0.71 gN), but was not different from zero in the hGH group (-2.32 +/- 1.66 gN). It is concluded that synthetic hGH administered after operation has beneficial effects on the whole-body nitrogen economy, as indicated by the unchanged capacity for protein synthesis in skeletal muscle, the preserved levels of muscle free glutamine, and improvement in the whole-body nitrogen balance. The effects of hGH on skeletal muscle protein and amino acid metabolism can explain the postoperative nitrogen-sparing effect attributed to hGH.