Human growth hormone immunoassay: two-antibody method using I-125 tracer

Insulin responsiveness of protein metabolism in vivo following bedrest in humans

To test the influence of bedrest on insulin regulation of leucine metabolism, six normal young men were subjected to a five-step hyperinsulinemic euglycemic clamp before and after 7 days of strict bedrest. A primed-constant infusion of [1-13C]leucine at 0.12 +/- 0.02 mumol.kg-1.min-1 was used. Before bedrest, the basal rate of appearance (Ra) of intracellular leucine and leucine oxidation were 2.79 +/- 0.17 and 0.613 +/- 0.070 mumol.kg-1.min-1, respectively. Insulin caused a dose-dependent reduction of the intracellular leucine Ra and leucine oxidation to a minimum of 1.64 +/- 0.08 and 0.322 +/- 0.039 mumol.kg-1.min-1, respectively, in nonbedrested subjects (P less than 0.001). Insulin also caused a dose-dependent reduction of plasma leucine concentration from 95 +/- 4 to 38 +/- 2 mumol/l (P less than 0.001). After bedrest, subjects exhibited decreased glucose tolerance and increased endogenous insulin secretion, but basal and insulin-suppressed intracellular leucine Ra and leucine oxidation rates were not different from control. Magnetic resonance imaging of the back and lower extremities revealed a 1-4% decrease in muscle volume and a 2-5% increase in fat volume secondary to bedrest. Bedrest also resulted in a negative nitrogen balance as compared with the control period, with an average cumulative loss of 6.3 g of nitrogen after 6 days. Urinary 3-methyl-L-histidine excretion was unchanged by bed rest. Thus because negative nitrogen balance and skeletal muscle atrophy occurred in six rested subjects in the absence of changes in the two indices of protein breakdown used in this study (3-methyl-L-histidine release and leucine release), it seems likely that muscle protein synthesis was inhibited.

Small cell undifferentiated carcinoma of the esophagus. Case report with hormonal studies

This report details clinical and pathologic aspects of a case of small cell undifferentiated carcinoma of the esophagus. Transmission electron microscopic examination demonstrated neurosecretory granules, and indirect immunoperoxidase stain for adrenocorticotropic hormone (ACTH) was positive. However, the authors detected no abnormal hormone levels in urine or blood. The calculated tumor doubling time was approximately 2 days. The fulminant nature of this carcinoma was also evident from the rapid clinical progression in spite of surgical excision, radiotherapy, and chemotherapy.

The effect of diphenylhydantoin on metabolic and growth hormone changes during and after exercise

Metabolic and human growth hormone responses to exercise were investigated in six normal healthy subjects on two occasions with and without an oral dose of diphenylhydantoin (500 mg). Serum diphenylhydantoin concentrations were similar in all subjects and were just below the accepted therapeutic range for epileptic patients. There was no significant difference in blood lactate, pyruvate or glucose concentrations with diphenylhydantoin. Plasma free fatty acids, and blood glycerol and total ketone concentrations were greater after exercise following diphenylhydantoin. Significantly greater concentrations of human growth hormone occurred during exercise with diphenylhydantoin. Further investigation of the mechanisms by which diphenylhydantoin alters lipolysis and human growth hormone release would be of value as these metabolic and hormonal effects could influence exercise tolerance in athletics and other pursuits.

A controlled, prospective, randomized trial evaluating the metabolic effects of enteral and parenteral nutrition in the cancer patient

In order to evaluate the metabolic effects of enteral versus parenteral nutritional support in the cancer patient, patients with localized, squamous cell carcinoma of the distal esophagus were randomized to one of three nutritional regimens: oral feeding, jejunal feeding, or total parenteral nutrition (TPN). Patients were initially studied in the postabsorptive state and again two weeks after beginning, and while receiving, enteral or parenteral feedings. Radioisotopic tracer methods were utilized to evaluate parameters of glucose and alanine kinetics, and arterial substrate and hormone levels were measured. Arterial plasma glucose and blood lactate levels increased and plasma free fatty acid, serum triglyceride, and serum cholesterol levels decreased to comparable levels in patients receiving jejunal feedings or TPN. Changes in serum insulin, plasma glucagon, serum cortisol, serum growth hormone, and serum thyroxine were similar in patients receiving enteral and parenteral nutrition. Enteral and parenteral nutrition also had comparable effects on both alanine and glucose kinetics. In particular, both jejunal feedings and TPN were equally efficacious in markedly suppressing gluconeogenesis in the cancer patient. Our data would support the conclusion that there are few, if any, differences in the measured metabolic effects of enteral venous parenteral nutritional support in the group of cancer patients studied.

Familial dwarfism with high IR-GH: report of two affected sibs with genetic and epidemiologic considerations

Two sibs with high serum IR-GH dwarfism, born to first-cousin parents are described. Genetic analysis based upon 25 reported informative kindreds indicates that the condition has an autosomal recessive pattern of inheritance. Population evaluation and epidemiology of the affected subjects suggest that mutation rates of the gene determining the disease in non-Jewish populations could be as rare as 3.2 x 10(-5). However, its prevalence must be exceptionally high among endogamous Oriental Jewish groups derived from a common gene pool in historical times.

Failure of naloxone to alter growth hormone and prolactin levels in acromegalic and in hyperprolactinaemic patients

We examined the effects of high-dose intravenous naloxone administration in four acromegalic patients (mean serum growth hormone level 72 ng/ml) and in seven hyperprolactinaemic women (mean serum prolactin level 59 ng/ml), in order to assess whether this opiate antagonist would be effective in lowering growth hormone and prolactin levels. No effect was observed. This lack of effect suggests that an opioid pathway is not involved in the maintenance of elevated growth hormone or prolactin secretion in these patients. However, conclusions regarding the possible role of endogenous opioids in regulation of pituitary function in normal individuals cannot be drawn from this study.

The effect of somatostatin on metabolic and hormonal changes during and after exercise

The effect of intravenous somatostatin on blood levels of metabolites and hormones has been examined in normal subjects who performed a 30-minute period of bicycle exercises at 70% maximal exercise capacity. The results have been compared with control studies in the same subjects. Measurements were made of blood levels of lactate, glucose, free fatty acids, glycerol, acetoacetate, 3-hydroxybutyrate, insulin, glucagon, growth hormone (hGH) and prolactin. Growth hormone and glucagon release were suppressed during exercise with somatostatin and there was a subsequent elevation during recovery. There was slight post-exercise depression of insulin, but no alteration of plasma prolactin secretion. Blood glucose was reduced during exercise with somatostatin and increased during recovery. The elevation of ketone bodies after exercise was greater in the investigation with somatostatin, but there were no significant changes in other metabolites. Somatostatin, although causing inhibition of hGH release, appeared to have no significant effect upon fatty acid mobilization during exercise.

H-Y antigen in Swyer syndrome and the genetics of XY gonadal dysgenesis

The H-Y antigen is a plasma membrane antigen involved in the organogenesis of the mammalian testis. Its expression on human cells is determined by a Y-linked gene. Phenotypic females affected by 46,XY gonadal dysgenesis (Swyer's syndrome) can be either H-Y-positive or H-Y-negative. In this paper we report H-Y antigen and endocrine studies in a sibship with three affected sisters. Immunological studies were performed on two of the patients, and a clearly positive expression was detected in both cases. Endocrine studies consisted in the investigation of the hypothalamic-pituitary-gonadal axis, which revealed that gonadal hormone insufficiency is the only endocrine abnormality associated with the syndrome. A new genetic interpretation and calssification of XY gonadal dysgenesis is proposed.

Effect of fluphenazine on pituitary function in man

The growth hormone (hGH) and prolactin (hPRL) response to insulin induced hypoglycaemia was studied in six alcoholics on two occasions before and after treatment with a single intramuscular injection of fluphenazine (Modecate). On both occasions blood samples were taken at intervals before and after the intravenous injection of soluble insulin (0.1 u/kg body weight). The patients were investigated on the first occasion, 2-7 days after cessation of drinking and they all demonstrated an adequate hGH response. They then received an injection of fluphenazine (Modecate 12.5 mg) and were reinvestigated 1 week later. The hGH response to hypoglycaemia was significantly impaired after treatment with fluphenazine. Basal hPRL concentrations were significantly increased and increased concentrations of hPRL in response to hypoglycaemia occurred after treatment. We conclude that a single injection of fluphenazine (Modecate 12.5 mg) has a marked effect on hypothalamic-pituitary mechanisms controlling hGH and hPRL release.

The growth hormone response to insulin induced hypoglycaemia in alcoholics

The growth hormone response to insulin induced hypoglycaemia was studied in 7 alcoholic in-patients who had been abstinent for 2-11 days and in 10 normal controls. Blood samples were taken at intervals after the injection of soluble insulin (0-1 U/kg body weight). The growth hormone response was impaired in 4 of the alcoholics and the depression was not related to differences in blood glucose or plasma free fatty acids. The cortisol response was also impaired in the alcoholics. We conclude that alcoholics observed after alcohol withdrawal may have a depression of hypothalamic/pituitary function.

[Fatty acid patterns and glucose tolerance in Huntington's chorea (author's transl)]

Fatty acid patterns of plasma lipids and glucose-tolerance in Huntington's chorea. 25 patients with Huntington's chorea of various manifestation (9 predisposed symptomefree, 5 with light and 11 with severe manifestation) had studies of carbohydrate and lipid metabolism. These studies measured glucose-tolerance tests, insulin-, HGH-secretion, serum lipids and plasma fatty acid conposition of the cholesterylesters, triglycerides and phospholipids. The reactive insulin- but not HGH-levels were significantly raised, 32 % of the patients with Huntington's chorea had abnormal glucose-tolerance tests, compared with 3.2 % in a control group. Duration of symptoms correlated with higher cholesterol levels. Minor deviations were found in the fatty acid patterns in various lipid clases.

Altered growth hormone release in Huntington's chorea

Glucose tolerance tests have been performed on five patients with Huntington's chorea and no difference in response has been observed compared with seven controls. Insulin tolerance tests have been performed on 12 patients with Huntington's chorea and 10 controls. Blood samples were taken at regular intervals for 75 minutes and analysed for blood glucose, insulin, and growth hormone (HGH). There was no difference between the groups in the hypoglycaemia which developed. The patients, however, had an earlier elevation of HGH than the controls. The difference was highly significant (P less than 0.001, P less than 0.02) 30 and 35 minutes after the intravenous injection of insulin. The patients, although awake, ceased to have choreiform movements for at least the last 60 minutes of the insulin tolerance tests. Our observations of HGH release imply that hypothalamic activity is altered in Huntington's chorea. Further observations of HGH release may therefore be of value in its diagnosis.

Muscular exertion: a test of pituitary function in children

The elevated level of growth hormone after moderate standardized physical exercise was compared with that induced by intravenous arginine infusion and by insulin induced hypoglycemia in children with normal pituitary function. Tests were performed on 49 prepubertal children (34 boys and 15 girls); in 42 cases the increase was significant for all three tests, in 5 cases the response was minimal after insulin stimulation but normal after arginine and physical exertion; in 1 case arginine produced no response but the other tests were positive; in 1 case there was a response to arginine but none to insulin or physical exertion. The results indicate that frequently more than one test is necessary for the diagnosis of normal pituitary function; physical exertion being a physiologic test, is simple to perform, acceptable to the children and without side effects. It appears the test of first choice because it can be used in patients seen ambulatorily, other tests being performed in case of doubt or negative response.

Syndrome of growth resistance, obesity, and intellectual impairment with precocious puberty

A syndrome of growth resistance, obesity, and intellectual impairment with precocious puberty is described. Two girls presenting with many of the manifestations of the Prader-Willi syndrome, including growth resistance, obesity, and intellectual impairment, also exhibited precocious sexual maturation. It is suggested that this syndrome represents a hypothalamic disturbance closely related to the Prader-Willi syndrome and should be considered one of its variants.

Growth hormone in infant malnutrition: the arginine test in marasmus and kwashiorkor

1. Experiments in children and in animals seem to demonstrate that in marasmic malnutrition there is a reduction in the secretion of growth hormone. To study this problem the fasting, resting plasma concentrations of growth hormone were determined, before, and 45 and 60 min after, stimulation with an intravenous dose of arginine, in six infants with marasmus, in six infants with kwashiorkor and in five normal infants.

2. The values of plasma growth hormone (4·5 ± 0·97 ng/ml) in marasmic infants were significantly (P < 0·001) lower than those of the controls (7·8 ± 2·6 ng/ml), and responded little to stimulation with arginine (5·1 and 5·8 ng/ml at 45 and 60 min respectively), in contrast to those in the control group, which rose to 16·4 and 14·6 ng/ml. In children with kwashiorkor the values were very variable, but generally high, and showed little response (25·6 ± 13·3 before and 25·0 ± 17·6 and 14·2 ± 5·3 ng/ml at 45 and 60 min after stimulation respectively).

3. These results demonstrate that the responses of the hypophysis to deprivation of calories and protein (marasmus) and to protein deprivation (kwashiorkor) are different: in marasmus there is a progressive adaptation, with low secretion and poor reaction to stimulation, whereas in kwashiorkor the process is acute with high basal values of plasma growth hormone.