Disappearance of growth hormone from plasma of fetal and newborn sheep

1988 ◽  
Vol 254 (3) ◽  
pp. E318-E322 ◽  
Author(s):  
G. G. Power ◽  
K. T. Ball ◽  
P. D. Gluckman
Keyword(s):  
Growth Hormone ◽  
Volume Of Distribution ◽  
In Utero ◽  
Rapid Loss ◽  
Irreversible Loss ◽  
Fetal Sheep ◽  
Secretory Rate ◽  
Composite Tissue ◽  
Natural Birth ◽  
Plasma Gh

The disappearance of growth hormone (GH) from plasma was measured after a single intravenous injection in fetal and newborn sheep and fetal sheep after simulated birth in utero. The process was adequately described when separated into two exponential components, consistent with an inner (plasma) and outer (composite tissue) pool. Plasma clearance rate increased from 3.4 +/- 0.2 (SE, n = 6) in fetuses to 3.9 +/- 0.1 (n = 5) ml.min-1.kg-1 in newborns (P less than 0.05), but was not altered significantly after simulated delivery in utero. The volume of distribution decreased from 74 +/- 4 ml/kg before birth to 47 +/- 2 ml after natural birth (P less than 0.001). The basal secretory rate decreased from 2.4 +/- 0.2 before birth to 0.27 +/- 0.02 microgram/min after birth (P less than 0.001) and to a lesser extent after simulated delivery. The rate constant for irreversible loss, Kd, increased from 0.052 +/- 0.004 min-1 before birth to 0.093 +/- 0.002 min-1 after birth (P less than 0.001). Because plasma GH concentration in steady state equals secretory rate/(volume of distribution X Kd), one may calculate that 83% of the total decrease in GH, which occurs after birth, can be explained by diminished secretory rate, whereas 17% can be explained by more rapid loss from the plasma.

Growth and growth hormone kinetics in Holstein steer calves

1993 ◽  
Vol 73 (2) ◽  
pp. 277-285 ◽  
Author(s):  
G. J. Mears ◽  
G. B. Schaalje
Keyword(s):  
Growth Hormone ◽  
Body Weight ◽  
Average Daily Gain ◽  
Volume Of Distribution ◽  
Canola Meal ◽  
Metabolic Clearance ◽  
Grass Hay ◽  
Basal Plasma ◽  
Rumen Undegradable Protein ◽  
Plasma Gh

Average daily gain (ADG), basal plasma growth hormone (GH) concentration, and plasma GH kinetics following a bolus injection of GH were determined at birth and at 75, 150, 250, 350 and 450 kg body weight in 19 Holstein steer calves. From 100 kg body weight, calves were fed one of three diets: 85% grass hay and 15% concentrate; 85% grass hay and 15% concentrate with rumen undegradable protein (formaldehyde-treated canola meal); and, 85% concentrate and 15% grass hay. Addition of rumen undegradable protein to the hay-based diet did not (P > 0.05) increase ADG. However, ADG were higher (P < 0.001) for calves on the 85% concentrate diet. Calf basal plasma GH concentrations, plasma GH clearance rates, and GH secretion rates were not affected by either diet or ADG adjusted for the effect of diet. In contrast, body weight had a large effect on basal plasma GH concentration and plasma GH kinetics. As body weight increased, basal plasma GH concentration and GH half-life decreased. Growth hormone steady state volume of distribution, metabolic clearance rate and secretion rate per kg of body weight all decreased as calves became heavier. Key words: Steer growth, growth hormone, GH, basal GH, clearance, secretion

Improved method for single-bolus kinetic measurements using a noncleared reference indicator

1997 ◽  
Vol 273 (2) ◽  
pp. R828-R832
Author(s):  
G. G. Power ◽  
S. Bragg
Keyword(s):  
Intravenous Injection ◽  
Volume Of Distribution ◽  
Irreversible Loss ◽  
Kinetic Measurements ◽  
Fetal Sheep ◽  
Single Bolus ◽  
Calculated Volume ◽  
Near Term ◽  
Additional Reference ◽  
Circulatory Pattern

After intravenous injection of a tracer as a single bolus, its concentration decreases as it mixes with the plasma, disperses throughout the circulation, and enters body pools. Kinetic values that are dependent on early concentrations may be in considerable error because mixing is not instantaneous throughout the circulation, and this problem is particularly acute in the mammalian fetus, with its distinctive circulatory pattern. To minimize this error, a method was developed in which the noncleared reference tracer 125I-labeled albumin was injected together with a representative, rapidly cleared metabolite 14C-labeled palmitic acid, and the former was used to correct for mixing delay. A total of 19 disappearance curves were studied after intravenous injection into seven near-term fetal sheep. Kinetic values were calculated with and without correction for mixing delay. Taking account of mixing delay increased the calculated volume of distribution 41% [from 44 +/- 4 (SE) to 62 +/- 3 ml/kg, P < 0.001], increased plasma clearance rate 13% (from 41 +/- 2 to 47 +/- 1 ml-min-1.kg-1, P < 0.002), decreased the rate constant for irreversible loss 26% (from 1.05 +/- 0.07 to 0.78 +/- 0.04 min-1, P < 0.001), and increased the calculated effective half-life 26% (0.71 +/- 0.06 to 0.90 +/- 0.05 min, P < 0.001). Thus use of the additional reference marker significantly altered calculated results and provided values believed to more accurately describe rapid disappearance from the central mixing compartment into metabolic pools.

scholarly journals CD34+ human marrow cells that express low levels of Kit protein are enriched for long-term marrow-engrafting cells

Blood ◽  
1996 ◽  
Vol 87 (10) ◽  
pp. 4136-4142 ◽  
Author(s):  
I Kawashima ◽  
ED Zanjani ◽  
G Almaida-Porada ◽  
AW Flake ◽  
H Zeng ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Marrow Cell ◽  
In Utero ◽  
Fetal Sheep ◽  
Hematopoietic Stem ◽  
Show Evidence ◽  
Marrow Cells

Using in utero transplantation into fetal sheep, we examined the capability of human bone marrow CD34+ cells fractionated based on Kit protein expression to provide long-term in vivo engraftment. Twelve hundred to 5,000 CD34+ Kit-, CD34+ Kit(low), and CD34+ Kit(high) cells were injected into a total of 14 preimmune fetal sheep recipients using the amniotic bubble technique. Six fetuses were killed in utero 1.5 months after bone marrow cell transplantation. Two fetuses receiving CD34+ Kit(low) cells showed signs of engraftment according to analysis of CD45+ cells in their bone marrow cells and karyotype studies of the colonies grown in methylcellulose culture. In contrast, two fetuses receiving CD34+ Kit(high) cells and two fetuses receiving CD34+ Kit- cells failed to show evidence of significant engraftment. Two fetuses were absorbed. A total of six fetuses receiving different cell populations were allowed to proceed to term, and the newborn sheep were serially examined for the presence of chimerism. Again, only the two sheep receiving CD34+ Kit(low) cells exhibited signs of engraftment upon serial examination. Earlier in studies of murine hematopoiesis, we have shown stage-specific changes in Kit expression by the progenitors. The studies of human cells reported here are in agreement with observations in mice, and indicate that human hematopoietic stem cells are enriched in the Kit(low) population.

scholarly journals Circulating levels of growth hormone in postural orthostatic tachycardia syndrome

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Madeleine Johansson ◽  
Fabrizio Ricci ◽  
Janin Schulte ◽  
Margaretha Persson ◽  
Olle Melander ◽  
...  
Keyword(s):  
Heart Rate ◽  
Growth Hormone ◽  
Orthostatic Intolerance ◽  
High Sensitivity ◽  
Symptom Assessment ◽  
Postural Orthostatic Tachycardia Syndrome ◽  
Daily Life Activities ◽  
Median Plasma ◽  
Symptom Assessment Scale ◽  
Plasma Gh

AbstractPostural orthostatic tachycardia syndrome (POTS) is a cardiovascular autonomic disorder with poorly understood etiology and underlying pathophysiology. Since cardiovascular morbidity has been linked to growth hormone (GH), we studied GH levels in patients with POTS. We conducted an age-sex-matched case–control study in patients with POTS (age 31 ± 9 years; n = 42) and healthy controls (32 ± 9 years; n = 46). Plasma GH levels were measured using high-sensitivity chemiluminescence sandwich immunoassay. The burden of orthostatic intolerance symptoms was assessed by the Orthostatic Hypotension Questionnaire (OHQ), consisting of a symptom assessment scale (OHSA) and a daily activity scale (OHDAS). POTS patients had significantly higher composite OHQ score than controls, more symptoms and less activity. Supine heart rate and diastolic blood pressure (BP), but not systolic BP, were significantly higher in POTS. Median plasma GH levels were significantly lower in POTS (0.53 ng/mL) than controls (2.33 ng/mL, p = 0.04). GH levels were inversely related to OHDAS in POTS and supine systolic BP in POTS and controls, but not heart rate neither group. POTS is associated with lower GH levels. Impairment of daily life activities is inversely related with GH in POTS. A higher supine diastolic BP is inversely associated with GH levels in POTS and healthy individuals.

The Circulating Growth Hormone (GH)-Binding Protein Complex: A Major Constituent of Plasma GH in Man*

Endocrinology ◽  
1988 ◽  
Vol 122 (3) ◽  
pp. 976-984 ◽  
Author(s):  
GERHARD BAUMANN ◽  
KLAUS AMBURN ◽  
MELISSA A. SHAW
Keyword(s):  
Growth Hormone ◽  
Protein Complex ◽  
Binding Protein ◽  
Major Constituent ◽  
Plasma Gh

Growth hormone and somatostatin gene expression in pituitary adenomas with active acromegaly and minimal plasma growth hormone elevation

1990 ◽  
Vol 122 (6) ◽  
pp. 745-752 ◽  
Author(s):  
Patrick Pagesy ◽  
Jacques Y. Li ◽  
Françoise Rentier-Delrue ◽  
Olivier Delalande ◽  
Yves Le Bouc ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Northern Blot Analysis ◽  
Secretory Activity ◽  
Ultrastructural Level ◽  
Wide Range ◽  
Igf I ◽  
Gh Gene ◽  
Basal Plasma ◽  
Active Acromegaly ◽  
Plasma Gh

Abstract. Some patients with active acromegaly have elevated plasma IGF-I concentrations with only minimal elevation of plasma GH. We compared adenomatous GH and SRIH expression in 3 such patients (patients No. 1, 2 and 3; basal plasma GH level < 4 μg/l) and in 3 acromegalic patients with high basal plasma GH level (patients No. 4, 5 and 6; 51.7 ± 16.1 μg/l, mean ± sem). By immunocytochemistry, all the tumours proved to be somatotropic adenomas. At the ultrastructural level, signs of low secretory activity were observed in adenomas from patients No. 2 and 3. Perifused adenoma cells of patients No. 1, 2 and 3 released very little GH compared with those of patients No. 4, 5 and 6 (1± 0.37 vs 51.5± 34.1 μg · (10−6 cells) · min−1, p< 0.001). Adenoma SRIH content was 65.7 and 30.6 pg/mg proteins in patients No. 1 and 2, whereas it was undetectable in the others (patients No. 4, 5 and 6). Northern blot analysis showed that the GH gene was poorly expressed in the adenomas from patients No. 1, 2 and 3 compared with the adenomas from patients No. 4, 5 and 6. SRIH mRNA was detected in all 6 adenomas. However, the signal was more intense in the adenomas from patients No. 1, 2 and 3 than in those from patients No. 4, 5 and 6. In conclusion, because of the variability of the biosynthetic and secretory potential of the somatotropic adenomas, patients harbouring this type of pituitary tumours can exhibit a wide range of plasma GH levels. In acromegaly with minimal elevation of plasma GH, the synthesis of SRIH by the adenoma cells themselves could play a role in the inhibition of GH expression.

The growth hormone axis and cognition: empirical results and integrated theory derived from giant transgenic mice

1999 ◽  
Vol 77 (12) ◽  
pp. 1874-1890 ◽  
Author(s):  
C D Rollo ◽  
C V Ko ◽  
JG A Tyerman ◽  
L J Kajiura
Keyword(s):  
Growth Hormone ◽  
Accelerated Aging ◽  
Error Rates ◽  
Transgenic Rat ◽  
Brain Functioning ◽  
Neuroendocrine Mechanisms ◽  
System Functioning ◽  
Plasma Gh ◽  
Enhanced Learning

Sleep is required for the consolidation of memory for complex tasks, and elements of the growth-hormone (GH) axis may regulate sleep. The GH axis also up-regulates protein synthesis, which is required for memory consolidation. Transgenic rat GH mice (TRGHM) express plasma GH at levels 100-300 times normal and sleep 3.4 h longer (30%) than their normal siblings. Consequently, we hypothesized that they might show superior ability to learn a complex task (8-choice radial maze); 47% of the TRGHM learned the task before any normal mice. All 17 TRGHM learned the task, but 33% of the 18 normal mice learned little. TRGHM learned the task significantly faster than normal mice (p < 0.05) and made half as many errors in doing so, even when the normal nonlearners were excluded from the analysis. Whereas normal mice expressed a linear learning curve, TRGHM showed exponentially declining error rates. The contribution of the GH axis to cognition is conspicuously sparse in literature syntheses of knowledge concerning neuroendocrine mechanisms of learning and memory. This paper synthesizes the crucial role of major components of the GH axis in brain functioning into a holistic framework, integrating learning, sleep, free radicals, aging, and neurodegenerative diseases. TRGHM show both enhanced learning in youth and accelerated aging. Thus, they may provide a powerful new probe for use in gaining an understanding of aspects of central nervous system functioning, which is highly relevant to human health.

PITUITARY FUNCTION AFTER YTTRIUM IMPLANTS AS MEASURED BY PLASMA GROWTH HORMONE LEVELS

1971 ◽  
Vol 50 (1) ◽  
pp. 41-50 ◽  
Author(s):  
HELEN J. STEWART ◽  
E. A. BENSON ◽  
M. MAUREEN ROBERTS ◽  
A. P. M. FORREST ◽  
F. C. GREENWOOD
Keyword(s):  
Breast Cancer ◽  
Growth Hormone ◽  
Advanced Breast Cancer ◽  
Adrenal Function ◽  
Advanced Breast ◽  
Pituitary Function ◽  
Post Mortem ◽  
Plasma Growth Hormone ◽  
Fasting Level ◽  
Plasma Gh

SUMMARY Plasma growth hormone (GH) levels during insulin hypoglycaemia were measured in 30 women with implants of 90Y in the pituitary for advanced breast cancer. There was evidence of continued pituitary activity in six patients (20%), the rise in plasma GH level being greater than 4 ng/ml during hypoglycaemia. Thirteen patients (43%) were regarded as having complete ablations because they had no GH response and a fasting level of less than 4 ng/ml. In the remaining 11 patients (37%) there was no rise in the GH level during hypoglycaemia, but there were significant fasting levels. From the post-mortem evidence it was concluded that these patients also had adequate ablations. This test is shown to be of more value in estimating residual pituitary function than routine tests of thyroid or adrenal function.

Is there a place for urinary growth hormone measurement?

1993 ◽  
Vol 128 (3) ◽  
pp. 197-201 ◽  
Author(s):  
Maria N Moreira-Andrés ◽  
Francisco J Cañizo ◽  
Federico Hawkins
Keyword(s):  
Growth Hormone ◽  
Screening Method ◽  
Small Sample ◽  
Point Of View ◽  
Intrasubject Variability ◽  
Gh Secretion ◽  
Lack Of Information ◽  
Low Levels ◽  
Plasma Gh ◽  
Serum Gh

The evaluation of growth hormone (GH) secretion is an important problem in pediatric endocrine practice. The diagnosis of GH insufficiency is based on the finding of a "blunted" GH response to GH provocative tests or on the demonstration of a decreased endogenous secretion. From a practical point of view, these methods are uncomfortable, expensive and time consuming. Recently, very sensitive specific assays to measure human GH in urine have been developed. We present a discussion of available data on these tests in order to estimate their role in the evaluation of a short or slowly growing child. The present available assays allow measuring very low levels of GH in a small sample of untreated urine. The main limitations of urinary GH measurement are the intrasubject variability, wide normal range, overlapping results in several GH secretory states and lack of information on GH pulsatility. However, most of these limitations also apply to other tests of GH secretion. The advantage of urinary GH tests is that they provide, in an easy procedure, information on serum GH concentration. There is good correlation between urinary and serum GH concentration and several findings suggest that urinary GH excretion reflects changes in plasma GH levels during the period of urine collection. Therefore, the usefulness of urinary GH measurement is that of a simpler and cheaper screening method for assessing integrated serum GH concentration in clinical practice.

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