Human Growth Hormone Levels Research Articles

Growth hormone response to insulin-induced hypoglycemia in diabetes secondary to chronic calcific pancreatitis.

Human growth hormone (HGH) responses to insulin-induced hypoglycemia were measured in 6 patients with diabetes secondary to chronic calcific pancreatitis (pancreatic diabetes). A group of carefully matched control subjects was similarly investigated. Despite induced hypoglycemia of a magnitude not significantly different from the controls at 30 min, and significantly greater at 45 and 60 min, patients with pancreatic diabetes responded with significantly impaired peak HGH levels. The interpretation of these findings is uncertain, although the observation that children with cystic fibrosis of the pancreas show similarly blunted responses suggests that a pancreatic stimulus to HGH secretion may be lacking.

Secretion of growth hormone in the diencephalic syndrome of childhood

Two children with the clinical and laboratory features of the diencephalic syndrome of Russell are described. Both had high fasting levels of human growth hormone (HGH), incompletely suppressed by hyperglycemia; in the one patient tested, HGH was not further elevated by hypoglycemia. The elevated, poorly suppressed HGH levels returned to normal, accompanied by weight gain, in one child after successful radiotherapy. It is suggested that the tumor impinging on the hypothalamus caused release of HGH not responsive to the usual physiologic effects of blood glucose fluctuations. This might account for the apparent anomaly of marked diminution in body fat with normal or excessive growth.

Plasma growth hormone in hyperthyroidism and obesity: Effect of propranolol infusion

In normal subjects the intravenous infusion of propranolol caused a significant rise in plasma human growth hormone (HGH) levels with a transient decrease in blood free fatty acids (FFA) and no significant change in blood glucose. The plasma HGH response to propranolol was decreased and delayed in patients with hyperthyroidism but became normal after treatment. The plasma HGH rose only very slightly in obese subjects after propranolol infusion. The blood FFA response to propranolol was almost normal in obesity but absent in hyperthyroidism.

Increase in plasma growth hormone concentration in man after infusion of adrenaline-propranolol.

SUMMARY Plasma human growth hormone (HGH) concentrations were compared during four tests in which 0·9% NaCl solution only, propranolol, adrenaline or propranolol plus adrenaline were infused into six healthy volunteers. In five subjects, HGH levels during the infusion of saline, propranolol or adrenaline showed no significant increase and were virtually identical. During the test with propranolol plus adrenaline, however, there was an increase after adrenaline in spite of concomitant hyperglycaemia. The sixth volunteer showed a wide range of apparently spontaneous and irregular variations in HGH values throughout each of the four tests. These findings support the view that α-receptors stimulate and β-receptors depress HGH secretion, and show that adrenergically stimulated HGH secretion in man is not inhibited by hyperglycaemia.

Normal lactation and blood growth hormone studies

Plasma human growth hormone (HGH) was measured by a radioimmunoassay method both in a fasting resting state and during an insulin-induced hypoglycemic episode. There were 35 nonlactating control and 26 lactating nursing women tested in the late postpartum period. No statistically significant differences were demonstrated in either the blood glucose or plasma HGH levels. The significance of these findings is discussed in relation to the control of normal lactation and to the possible presence of a separate prolactin hormone in the human subject.

Hormonal Relationships During the Menstrual Cycle

Physiologic fluctuation of follicle-stimulating hormone (FSH), luteinizing hormone (LH), human-growth hormone (HGH), and progesterone concentrations in serum samples of women with ovulatory menstrual cycles were determined by radioimmunoassay and protein-binding assay. During the follicular phase of the cycle, the tonic secretion of FSH showed an initial rise followed by a progressive fall toward the midcycle. In contrast, LH secretion showed a steady increase. A clear elevation of progesterone concentration was observed 48 hours after the onset of a simultaneous surge of LH and FSH at midcycle. Progesterone levels rose rapidly reaching maximal concentration (mean 12.2 mμg/ml) five days after LH surge and remained elevated for five to six days. Thereafter, progesterone levels fell rapidly to an undetectable level on the day after onset of menstruation. This was accompanied by a significant elevation of the FSH and LH levels from their low concentration observed during the late luteal phase. Human-growth hormone levels observed while the patient was in a fasting, ambulant state showed a progressive rise reaching a peak just prior to LH surge and there was a random fluctuation during luteal phase of the cycle.

Human growth hormone secretion in normal adult subjects during and after exposure to cold.

ABSTRACT Eight experiments on human growth hormone (HGH) secretion during and after 1- or 2-hr cold exposure (4 C) were undertaken in 2 male and 4 female normal adult subjects. Body temperatures decreased to less than 35 C at 60 to 90 min after cooling was commenced. NEFA increased to 113–267% of the initial value during or after cooling. Serum cortisol showed only a slight increment ranging from 2.4 to 9.7 μg/100 ml. No increase in serum HGH level was found during cold exposure for 1 or 2 hr, but a significant increment ranging from 3.1 to 13.5 ng/ml was observed on re warming in any case with or without prior oral administration of 20 mg beta blockade (propranolol).

Hormonal changes during ribose-induced hypoglycemia.

Plasma levels of insulin and human growth hormone (HGH) were measured in healthy adults after oral or intravenous administration of the pentose sugar D-ribose. Increased plasma levels of insulin were recorded after both oral and intravenous ribose; there was no consistent change in plasma levels of HGH after administration of ribose by either route. It is suggested that insulin release occurs at such times and in amounts as may account at least in part for the hypoglycemie effect of this pentose.

The role of starvation, hypoglycemia, and adrenergic blockade on growth hormone secretion in obesity.

AbstractThe effects of starvation and refeeding on the circulating levels of human growth hormone (HGH) of seven obese subjects were studied with and without alpha and beta adrenergic blockade during an insulin tolerance test (ITT). The tests were performed during baseline, total fast, and refeeding periods. Autonomic blockade during starvation was not performed. The degrees of hypoglycemia produced during the mean baseline ITT before and after blockade and in the fasting period were comparable and associated with HGH levels of similar response. During refeeding, mean fasting glucose levels before and after blockade were higher than in control and fasting periods. The insulin‐induced hypoglycemia effect was comparable in percentage decrease, although absolute levels of hypoglycemia were less. There was correspondingly less response of HGH to this stimulus. This indicates that HGH secretion is normal in obesity provided sufficient hypoglycemia is produced a not apparently affected by circulating catecholamine levels.

Effect of changes in plasma free fatty acids level on secretion of human growth hormone.

The relationship between the changes of plasma free fatty acids (FFA) and human growth hormone (HGH) levels was investigated in normal young male subjects.The administration of nicotinic acid with its concomitant lowering of plasma FFA was followed by a rise of plasma HGH. The HGH rise could be inhibited by the simultaneous administration of heparin which prevented the fall of plasma FFA, or by glucose administration. The administration of heparin alone resulted in an increase of plasma HGH also in association with the fall of plasma FFA in the absence of any changes in plasma glucose levels. The rise of plasma HGH failed to occur when plasma FFA was kept elevated or when glucose was given.From these results, it was suggested that the fall of plasma FFA has a stimulatory effect and in turn, the elevated plasma FFA has an inhibitory effect on HGH secretion.

Metabolic clearance and production rates of human growth hormone.

The metabolic clearance rate (MCR) of human growth hormone (HGH) was determined by the constant infusion to equilibrium technique utilizing HGH-(125)I. 22 control subjects had a MCR of 229 +/-52 ml/min (mean +/-SD). No difference was evident between sexes, or between various age groups. Patients with acromegaly demonstrated normal MCR's. Moreover, acute elevations of plasma growth hormone concentrations in normal subjects did not alter the MCR of HGH. The MCR was relatively constant from day to day and within the day when subjects were evaluated in the supine position. In contrast, the assumption of the upright position was associated with a mean 24% decrease in the MCR. These results were contrasted with the MCR of HGH observed in a small number of patients with altered thyroid function or diabetes mellitus. In six patients with hypothyroidism the MCR (131 +/-36 ml/min) was significantly decreased (P < 0.001); whereas the MCR in eight patients with hyperthyroidism (240 +/-57 ml/min) did not differ from control subjects. The MCR in eight patients with insulin-independent diabetes mellitus (IID) (185 +/-41 ml/min) and in eight patients with insulin-dependent diabetes mellitus (IDD) (136 +/-31 ml/min) were significantly different from control subjects (P = < 0.05 and P = < 0.001, respectively). These data were interpreted to indicate that the plasma HGH-removing mechanism(s) is not saturated at physiologic plasma HGH levels, that plasma HGH levels alone may not permit distinction between variations in pituitary release of the hormone and its rate of clearance from the plasma, and that the estimation of the MCR of HGH may help clarify the mechanism of abnormal plasma HGH responses to various stimuli. Production rates of HGH (PR) in control subjects (347 +/-173 mmug/min) were contrasted with hyperthyroid patients (529 +/-242 mmug/min, P < 0.05), hypothyroid patients (160 +/-69 mmug/min, P < 0.02), IID (245 +/-100 mmug/min, NS), and IDD (363 +/-153 mmug/min, NS). Considerable variability in the determination of the concentrations of immunoprecipitable HGH-(125)I and endogenous plasma HGH concentrations was encountered at apparent equilibrium conditions. Since both factors are necessary for the PR calculations, the wide 95% confidence limits of the PR's did not permit a clear interpretation of the significance of these observations.

Hormonal imbalance and the sarcomata.

A series of 11 patients suffering front sarcoma of either soft tissues or bone, and of various ages (2–92 years), has been studied in our Unit. It was observed that in the majority of the postpubertal patients the serum level of human growth hormone (HGH, STH, somatotrophin) was elevated above the mean figure for the Australian population, estimated by radio‐immuno‐assay. This figure is 2.4 γγ/ml serum, with a range of 0.3–7.7 γγ/ml (Lazarus). In the sarcomatous patients, this level was exceeded in six of the nine postpubertal adults, but not in the prepubertal children, or in the very aged, or in those with quiescent lesions. Clinical improvement varying from regression to total disappearance was observed when the raised serum level was promptly reduced to lower levels.

Insulin tolerance test in depression.

A RECENT investigation from this laboratory 1 demonstrated that psychotic depression is associated with low rates of glucose utilization (k) and high levels of serum insulin following glucose injection. Patients with neurotic depression did not demonstrate these abnormalities. This abnormality, a resistance to endogenous insulin, returned toward normal when the patient improved. These findings, which could not be accounted for by initial levels of serum human growth hormone (HGH), age, or nutritional state, suggested that psychotic depression is associated with a type of endogenous insulin resistance unlike that of any previously described condition. Recent studies by Steiner et al 2 and Shaw and Chance 3 have shown that the routine serum insulin radioimmunoassay measures both insulin and the insulin precursor, proinsulin, but that proinsulin is not biologically active until enzymatically degraded to insulin. It is, therefore, possible that the higher serum

Acromegaly: Treatment by Cryoablation

Results of cryoablation of pituitary adenomas in seven patients with acromegaly are described. Objective and subjective improvement, as well as reduction in human growth hormone (HGH) levels, occurred in each case with a minimum of complications and difficulties. Complete remission was not obtained in two patients, one of whom underwent the procedure on two occasions. Some clinical and biochemical improvement was observed in these patients as well as reduced HGH levels. The five patients who attained normal HGH levels reached this range within 1 month and usually within 5 days, postoperatively. They had satisfactory clinical remissions as well as of the chemical signs of acromegaly. In several instances some or most of normal pituitary function was maintained despite apparent satisfactory destruction of the HGH-secreting tumor. In our experience, cryohypophysectomy is a relatively simple and safe procedure that has proved effective in the treatment of acromegaly.

Effects of 24 hour REM deprivation on serum growth hormone levels in humans : E. Othmer, V. Daughaday, and S. Guze (St. Louis, Mo., U.S.A.)

Effects of 24 hour REM deprivation on serum growth hormone levels in humans : E. Othmer, V. Daughaday, and S. Guze (St. Louis, Mo., U.S.A.)

Human growth hormone levels during the menstrual cycle

The normal patterns of human growth hormone (HGH) secretion in an ovulatory mentrual cycle were studied. Nineteen normal subjects recorded daily basal body temperatures (BBT). Their mean day of BBT rise was 15.6. They were each studied on day 5 and day 25 of the cycle with an insulin tolerance test in a fasting ambulatory state using 0.1 unit of regular insulin per kilogram as a stimulus. Measurements of blood glucose and plasma HGH showed no significant difference between the two tests. Fasting nonesterified fatty acid levels (NEFA) were also measured and these were not different. One subject was followed through an ovulatory cycle with daily fasting basal blood samples and these were analyzed for their glucose and HGH content. Although the glucose level did not change the HGH level rose at ovulation and premenstrually. It is concluded that HGH secretion does not change significantly between the proliferative and the secretory phases of the menstrual cycle.

Metabolic response to simultaneous infusion of epinephrine and Propranolol in obese adolescents

Eighteen studies were performed in 5 grossly obese adolescents in order to determine whether or not epinephrine and/or Propranolol are capable of decreasing the hyperinsulinemia characteristic of obese subjects and to study the metabolic response during the administration of these drugs. When epinephrine (6 μg./min.) was infused during a protein-glucose meal, there was a 50 per cent (or greater) decrease in the release of immunoreactive insulin as compared with the response to protein-glucose alone. However, the basal level of immunoreactive insulin was unchanged. There were also a marked hyperglycemia as well as a concomitant rise in the plasma free fatty acids. Plasma level of immunoreactive human growth hormone were undetectable. Epinephrine (10 μg./min.) in combination with Propranolol (80 μg./min.) resulted in a marked decrease in both the basal level and the subsequent release of immunoreactive insulin. Hyperglycemia was present and the plasma free fatty acids showed a precipitous fall. One patient had a brisk immunoreactive growth hormone response of 7 mμg./ml. after cessation of the infusion. When epinephrine (2 μg./min.) was simultaneously infused with Propranolol (80 μg./min.) only a slight decrease in the basal level of immunoreactive insulin was observed. The inhibition of the subsequent insulin release was mild and transitory. Again hyperglycemia occurred and the plasma levels of immunoreactive growth hormone were almost undetectable. Propranolol alone (80 μg./min.) did not affect the basal level or the subsequent release of immunoreactive insulin. One subject had a peak plasma immunoreactive growth hormone value of 5.9 mμg./ml. shortly after the infusion began. It is concluded that Propranolol and epinephrine in specific dose combinations have a synergistic action on the inhibition of insulin release in obese adolescents.

Growth hormone and glucose interrelationships in diabetes: studies with insulin infusion during continuous blood glucose analysis.

ABSTRACT To examine changes in plasma levels of human growth hormone (HGH) in severe diabetics under conditions resembling hypoglycemic reactions, 8 diabetics and 6 normal subjects were given insulin infusions at a constant rate during continuous automated blood glucose (BG) analysis. HGH was determined by radioimmunoassay at frequent intervals. All subjects tested who reached a BG nadir of 35 mg/100 ml had HGH increases. Other HGH increases occurred also during hyperglycemia in 7 tests, but only in diabetics. Mean increases in plasma HGH were similar in normals and in diabetics and whether during hypoglycemia or during hyperglycemia. No hyperglycemic or hypoglycemic effect of HGH increases was discernible. The method proved to be uniquely suited for exploring HGH and BG changes during the infusion of insulin. Diabetics differed from normals by augmenting circulating levels of HGH during hyperglycemia, whether or not BG was decreasing at the time the observations were made.

Growth hormone response to gastrectomy.

The fluctuation of the plasma level of human growth hormone (HGH), in relation to blood sugar and plasma non-esterified fatty acid (NEFA) levels, was investigated, both before and after surgery, in thirty-four subjects, who had received gastrectomy due to either peptic ulcer or gastric cancer. The level of HGH was markedly elevated immediately after the commencement of surgery and arrived at a peak after 30 to 60 minutes. Thereafter the level gradually fell despite the continuation of surgery. Up untill the seventh postoperative day the levels during fasting showed no marked fluctuation. These HGH fluctuations bore no definite relationship to the nature of intra-operative infusions, age, sex, obsity or magnitude of surgical stress. From the fact that the elevation of NEFA release followed the elevation of HGH, it is recognized that increased release of HGH upon surgical stress greatly contributes to fat metabolism during this period. It is also suggested that the release of HGH might induce a fall in glucose utilization resulting a diabetogenicity immediately after surgical stress.

Plasma Human Growth Hormone Levels 4 Hours after Breakfast in Adolescent Twins and Adults

Plasma Human Growth Hormone (HGH) levels were determined in 176 healthy school children, 74 monozygotic and 14 dizygotic twins of 13-to 18-year-old, and in 34 healthy adult subjects 4 hrs. after the test breakfast. There was a considerable variation in plasma HGH concentrations, but most samples showed the values of 0.25mμg/ml to 40mμg/ml. The wide distribution of plasma HGH was especially noted in 13-and 14-year-old subjects in both sexes. In the male subjects, a definite difference in the distribution was noted between the 13-to 14-year-old school children and the 16-year-old or older subjects. In the female subjects, the difference was not so noticeable as in the male subjects. No correlation was noted between the plasma HGH levels and physical size of the subjects, nor between the values of plasma HGH in individual twins.