Intersubject viability in growth hormone time course during different types of work

This study addresses the question of variability of immunoreactive human growth hormone (IRHGH) response to the following types of muscular exercise. 1) One hour of submaximal exercise with restarting for 30 min after 20 min of recovery. Three types of responses were observed: a rise of [IRHGH] occurred in response to muscular activity; [IRHGH] was maintained at rest level during the first bout and then rose in the second bout; or [IRHGH] rose during the first bout and was no longer modified by the restarting. 2) Thirty minutes of heavy exercise. In some subjects [IRHGH] change was almost linear with time, reaching very high values and dropping as soon as exercise had stopped, whereas in others peak values were similar to those of submaximal exercise but, in contrast, plateaued during recovery. 3) One hour of exercise performed either continuously or with alternate sequences of 30-s exercise and 30-s pause. In intermittent exercise, some subjects displayed a similar time course of [IRHGH] as in continuous exercise and others displayed markedly high values. 4) One hour of submaximal exercise at three different intensities carried out at ambient temperatures of 24 and 33 degrees C. At 33 degrees C, in some subjects, [IRHGH] time course at the three intensities was unchanged at 33 degrees C compared with that at 24 degrees C, whereas the maximal value increased in another subject up to 150 ng X ml-1. A significant intrasubject consistency to a given type of exercise was evident over several months. The study emphasizes that caution should be used in drawing definite conclusions from averaged results with high variability.

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DOSE REGIMENS OF HUMAN GROWTH HORMONE: EFFECTS OF CONTINUOUS INFUSION AND OF A GELATIN VEHICLE ON GROWTH IN RATS AND RATE OF ABSORPTION IN RABBITS

Journal of Endocrinology ◽

10.1677/joe.0.0870303 ◽

1980 ◽

Vol 87 (2) ◽

pp. 303-312 ◽

Cited By ~ 17

Author(s):

P. MARY COTES ◽

W. A. BARTLETT ◽

ROSE E. GAINES DAS ◽

P. FLECKNELL ◽

R. TERMEER

Keyword(s):

Growth Hormone ◽

Human Growth Hormone ◽

Plasma Levels ◽

Time Course ◽

Human Growth ◽

Daily Injection ◽

Glycine Buffer ◽

Hormone Effects ◽

Rate Of Absorption ◽

Hypophysectomized Rats

Different methods for administration of human growth hormone (hGH) have been examined with a view to efficient use of the limited amounts of hGH at present available for clinical use. We found that in hypophysectomized rats (1) hGH administered by continuous subcutaneous infusion induced a greater increase in body weight (referred to throughout as growth) than hGH administered by intermittent (daily) injection and (2) intermittent injections of hGH dissolved in 16% gelatin induced more growth than hGH dissolved in a glycine buffer. It was further found that (1) hGH dissolved in 16% gelatin compared with hGH dissolved in a glycine buffer induced lower maximal levels of immunoreactive plasma hGH and between 7 and 9 h after treatment higher plasma levels when injected subcutaneously in rabbits, (2) 125I-labelled hGH added as a tracer to hGH in gelatin was removed more slowly from subcutaneous injection sites in rabbits than 125I-labelled hGH given with hGH in glycine buffer and (3) changes in the ratio of hGH to gelatin had little effect on the time-course of plasma levels of hGH in the rabbit. Addition of the protease inhibitors aprotinin or 6-aminohexanoic acid, to injection of hGH in gelatin or glycine did not induce any consistent increase in plasma levels of hGH.

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Kinetics of human growth hormone during submaximal exercise.

Journal of Applied Physiology ◽

10.1152/jappl.1974.37.6.826 ◽

1974 ◽

Vol 37 (6) ◽

pp. 826-830 ◽

Cited By ~ 44

Author(s):

C Lassarre ◽

F Girard ◽

J Durand ◽

J Raynaud

Keyword(s):

Growth Hormone ◽

Human Growth Hormone ◽

Human Growth ◽

Submaximal Exercise ◽

Kinetics Of

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THE EFFECT OF HUMAN GROWTH HORMONE ON SUBCUTANEOUS FAT THICKNESS IN HYPOSOMATOTROPHIC AND PANHYPOPITUITARY DWARFS

Journal of Endocrinology ◽

10.1677/joe.0.0390263 ◽

1967 ◽

Vol 39 (2) ◽

pp. 263-275 ◽

Cited By ~ 48

Author(s):

J. M. TANNER ◽

R. H. WHITEHOUSE

Keyword(s):

Growth Hormone ◽

Human Growth Hormone ◽

Subcutaneous Fat ◽

Human Growth ◽

Skinfold Thickness ◽

Normal Children ◽

Subcutaneous Fat Thickness ◽

Fat Thickness ◽

Metabolic Action ◽

Very High

SUMMARY The changes in skinfold thickness over the triceps and under the scapula were measured by the same observer every 3 months in 21 children before and during treatment with human growth hormone (HGH). Eleven hyposomatotrophic dwarfs showed a trebling of their rate of height growth during the first 3 months of treatment, and in all, the skinfolds, measuring mainly the amount of subcutaneous fat, decreased during the first 3 months of treatment. In some subjects in this group the skinfold values tended to rise gradually again as treatment progressed. All except two of these children had very high initial skinfold values; the average percentile was above the 75th before treatment, and at the 50th after 3 months of treatment. Four children, thought to have the same diagnosis, showed little or no height acceleration; they showed also little or no response in skinfold thickness; three of them were initially lean. Two small normal children and one child with gonadal dysgenesis responded neither in height nor in skinfolds. Three children with operated craniopharyngiomas responded well in height, but only one responded unequivocally in skinfolds. We think the response in dwarfed children represents a true metabolic action of HGH, since there was clinical evidence of a rise and not of a diminution in appetite. The possible implications of these results in the understanding of the physiological events underlying the normal curve of growth in fat in children, particularly at infancy and adolescence, are outlined.

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Growth hormone accelerates tubular acid secretion

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1991.260.6.r1036 ◽

1991 ◽

Vol 260 (6) ◽

pp. R1036-R1042 ◽

Cited By ~ 1

Author(s):

T. C. Welbourne ◽

M. J. Cronin

Keyword(s):

Growth Hormone ◽

Acid Secretion ◽

Time Course ◽

Recombinant Human Growth Hormone ◽

Human Growth ◽

Maximal Effect ◽

Volume Absorption ◽

Glomerular Filtrate ◽

Hypophysectomized Rats

The effect of growth hormone on tubular H+ secretion by the hypophysectomized and intact rat was studied in the isolated functioning kidney. Net acid secretion was estimated as the sum of HCO3- absorption plus NH+4 excretion. Kidneys from either intact or hypophysectomized rats were isolated and perfused over a 90-min time course during which either recombinant human growth hormone (GH), insulin-like growth factor-1 (IGF-1), porcine insulin, or vehicle was added; hormone response was then compared with the time controls. Compared with kidneys from intact rats, hypophysectomized rat kidneys exhibited a marked acidification defect, net H+ secretion, 13,530 +/- 600 vs. 17,860 +/- 810 (SE) nmol/ml of glomerular filtrate (GF). Administering GH (50 nM) increased net H+ secretion within 15 min in both hypophysectomized and intact groups to a maximum of 17,950 +/- 910 and 20,960 +/- 1,100 nmol/ml GF, respectively; neither insulin nor IGF-1 (50 nM) was able to mimic GH's effect. Addition of 1 mM amiloride completely abolished the GH-accelerated acid secretion and greater than 70% of the basal net acid secretion rate. Furthermore, GH-enhanced volume absorption was also abolished by amiloride, although neither NaCl nor glutamine absorption was affected. GH-accelerated acid secretion and coupled volume absorption could be observed at concentrations as low as 3.5 nM with half-maximal effect at 12 nM, which is within the range of GH concentration achieved during episodic GH surges. Finally administering GH in vivo to hypophysectomized rats enhanced net acid secretion and urinary acidification, consistent with accelerated tubular H+ secretion as one physiological expression of GH action.

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Time course of plasma growth hormone during exercise in humans at altitude

Journal of Applied Physiology ◽

10.1152/jappl.1981.50.2.229 ◽

1981 ◽

Vol 50 (2) ◽

pp. 229-233 ◽

Cited By ~ 19

Author(s):

J. Raynaud ◽

L. Drouet ◽

J. P. Martineaud ◽

J. Bordachar ◽

J. Coudert ◽

...

Keyword(s):

Growth Hormone ◽

Sea Level ◽

Time Course ◽

Human Growth ◽

Time Sequence ◽

La Paz ◽

Rate Of Increase ◽

Exercise Period ◽

Pronounced Reduction ◽

Exercise In Humans

The effects of hypoxia on growth hormone release during submaximal exercise were studied 1) in eight highlanders (HL) at 3,800 m (La Paz, Bolivia); and 2) in five lowlanders (LL) at sea level, after 5 days' sojourn at 2,850 m, and while breathing a hypoxic gas mixture (FIO2 - 0.15 corresponding to PIO2 at 2,850 m) 1 mo after returning to sea level. Concentrations of immunoreactive human growth hormone ([IRHGH]), blood glucose ([G]), free fatty acids ([FFA]), and lactate ([LA]) were determined repeatedly at rest, during 1 h of exercise, and after 1 h of recovery. Compared with LL, in HL, the resting value of [IRHGH] is higher, the rate of increase at the beginning of exercise is faster and earlier, but the mean maximal value reached at the end of exercise is similar. The response pattern in LL during the early stages of exposure to hypoxia resembles that of HL. No correlation was found between peak values of [IRHGH] and maximal values of [LA] and [FFA] or minimal values of [G]. The possible causes of the different time sequence observed in growth hormone dynamics during hypoxia are suggested: an alteration of the clearance of the hormone through a more pronounced reduction of hepatic blood flow or a difference in the state of the pituitary gland before the exercise begins. The study emphasizes the importance of characterizing time sequence of [IRHGH] by parameters other than the maximal value, e.g., by mean concentration computed over exercise period.

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