Influence of feeding and diet on diurnal patterns of plasma growth hormone and insulin in calves

1993 ◽  
Vol 73 (4) ◽  
pp. 987-991 ◽  
Author(s):  
G. J. Mears

Plasma GH concentrations were lower after feeding than before (newborn calves, P < 0.05; steers, P < 0.01). Calves fed concentrate had higher plasma insulin concentrations than those fed hay (P < 0.01). Meal feeding milk or concentrate, but not hay, elevated plasma insulin (P < 0.05). Diet type and feeding time relative to sampling time must be considered when measuring GH and insulin. Key words: Diurnal patterns, growth hormone, GH, insulin, calves

1986 ◽  
Vol 66 (4) ◽  
pp. 995-1001
Author(s):  
G. J. MEARS

Plasma concentrations of growth hormone (GH) and insulin were monitored in 11 chronically cannulated ovine fetuses and their mothers during the last month of gestation to obtain information on the role that these hormones have in determining fetal growth rate. Maternal plasma GH and insulin concentrations were independent of stage of gestation and lamb birth weights. Fetal plasma insulin concentrations were episodic in nature, independent of stage of gestation, and tended to be higher in fetuses that were heavier at birth. Fetal plasma GH concentrations were only slightly episodic in nature, were tenfold higher than maternal levels at 116–124 d gestation and increased by approximately another 25% prior to parturition. Fetal plasma GH concentrations were negtively correlated with lamb birth weights. In twin preparations, fetal plasma GH concentrations were significantly lower in the twin that was heaviest at birth. The lower GH concentrations found in faster growing fetuses are suggestive of a more rapid metabolic clearance of GH by the tissues of these animals. The results indicate that circulating fetal GH and, possibly, insulin are involved in determining the rate of ovine-fetal growth. Key words: Ovine birth weights, fetal GH, fetal insulin, fetal growth


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

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.


1976 ◽  
Vol 82 (2) ◽  
pp. 553-560 ◽  
Author(s):  
Anne Kristine Blom ◽  
Knut Hove ◽  
Jon J. Nedkvitne

ABSTRACT The pregnant ewe compensates the reduced carbohydrate availability in late pregnancy by increased fat combustion. The purpose of the present study was to examine the adaptation of plasma growth hormone (GH) and insulin levels to this change in energy substrate metabolism. Two groups of ewes were bled in the post-absorptive state at different stages of pregnancy. One group (7 animals) was fed adequately throughout pregnancy, while the other received a maintenance ration for non-pregnant sheep (28 animals). Plasma GH increased from averages from 2–3 to 8–14 ng/ml during the last month before lambing. Shearing of the wool combined with a cold stress resulted in a clearly detectable peak in plasma GH in the underfed sheep. No significant difference in plasma GH attributable to differences in diet could be detected in late pregnancy. Plasma insulin decreased steadily the last 5 weeks towards lambing, most in mothers with 3 lambs. Plasma free fatty acid levels (FFA) increased the last 2 months of pregnancy, most in the underfed sheep. GH and FFA were positively correlated (r = 0.50 and 0.30 in the two groups). It is concluded that the adaptation of the maternal metabolism to reduced carbohydrate - and eventually energy-availability in late pregnancy included lowering of insulin and enhancement of plasma GH levels. These adaptations were detectable under the present conditions the last 5–6 weeks before term.


PEDIATRICS ◽  
1973 ◽  
Vol 52 (1) ◽  
pp. 75-82
Author(s):  
Rosita S. Pildes ◽  
Daksha A. Patel ◽  
Menachem Nitzan

The present study was undertaken to determine the rate of glucose disposal in the pathogenesis of symptomatic neonatal hypoglycemia. Intravenous glucose (1 gm/kg) was injected rapidly into 11 hypoglycemic and eight control newborn infants. The percentage (mean ± SEM) disappearance rate per minute (Kt) was significantly higher (p &lt; 0.001) in the hypoglycemic newborn infants compared with that of the controls (2.8 ± 0.1 versus 1.2 ± 0.1, respectively). Baseline plasma insulin concentrations were significantly higher (p &lt; 0.01) in the hypoglycemic (16.8 ± 3.9µU/ml) than those of the controls (3.5 ± 1.0µU/ml). Baseline plasma growth hormone values in the hypoglycemic newborns were 16.6 ± 5.7 mµg/ml. Growth hormorne values rose in the hypoglycemic to 36 ± 10 mµg/ml at 10 minutes and to 64 ± 13 mµg/ml by 60 minutes.


Author(s):  
J.M. Dawson ◽  
D.E. Beever ◽  
P.J. Buttery ◽  
M. Gill

ß-adrenergic agonists are powerful repartitioning agents, increasing muscle protein accretion and reducing fat deposition in a variety of species. Their exact mode of action is not fully understood but some of their effects are similar to those elicited by exogenous growth hormone administration. Whilst there are few reports of plasma growth hormone (GH) concentrations being elevated in animals treated with ß-agonists, several in vitro studies have clearly demonstrated a direct stimulation of GH release from perifused or cultured pituitary or adenohypophyseal cells on administration of these agents. More recently, a brief, rapid rise in plasma GH has been demonstrated in rats infused intra-atrially with isoproterenol and this was sustained when the animals were pre-treated with somatotropin release inhibitory factor (somatostatin; SRIF) antiserum. This raises the possibility that ß-adrenergic agonists do stimulate GH release in vivo but that this response is rapidly counteracted by SRIF release.The aim of this work was to attempt to enhance the repartitioning effect of ß-adrenergic agonists by immunizing young cattle against SRIF whilst administering cimaterol.


1992 ◽  
Vol 68 (3) ◽  
pp. 667-676 ◽  
Author(s):  
R. W. Rosebrough ◽  
J. P. McMurtry ◽  
R. Vasilatos-Younken

Indian River male broiler chickens growing from 7 to 28 d of age were fed on diets containing energy: protein values varying from 43 to 106 MJ/kg protein and containing 0 or 1 mg triiodothyronine (T3)/kg diet to study effects on growth, metabolic hormone concentrations and in vitro lipogenesis. In vitro lipid synthesis was determined in liver explants in the presence and absence of ouabain (Na+, K+-transporting ATPase (EC 3.6.1.37) inhibitor) to estimate the role of enzyme activity in explants synthesizing lipid. Growth and feed consumption increased (P < 0.01) when the energy: protein value decreased from 106 to 71 MJ/kg protein; however, both variables decreased as the value was further decreased from 53 to 43 MJ/kg protein. Triiodothyronine depressed (P < 0.01) growth, but not food intake. Large energy:protein diets (> 53 MJ/kg protein) and dietary T3 lowered (P < 0.01) plasma growth hormone. Large energy:protein diets (> 53 MJ/kg protein) increased (P < 0.01) lipogenesis, plasma growth hormone (GH) and decreased plasma insulin-like growth factor 1 (IGF-1). Also, T3 decreased plasma GH, IGF-1 in vitro lipogenesis. Ouabain inhibited a greater proportion of in vitro lipogenesis in those explants synthesizing fat at a high rate. Both dietary T3 and in vitro ouabain decrease lipogenesis, but, when combined, the effects are not cumulative


1974 ◽  
Vol 27 (2) ◽  
pp. 167 ◽  
Author(s):  
JM Bassett

To determine the effects of feeding on plasma concentrations of insulin and growth hormone (GH) in sheep during the full 24 h of the normal feeding cycle, two experiments have been conducted on a group of 18 crossbred wethers.


1992 ◽  
Vol 127 (1) ◽  
pp. 38-43 ◽  
Author(s):  
Hans Herlitz ◽  
Olof Jonsson ◽  
Bengt-Åke Bengtsson

We investigated the relationship between mean plasma growth hormone (GH) concentration and cellular sodium transport in untreated and treated acromegaly. Seventeen patients (age 55±3 years) with active acromegaly were studied with respect to plasma GH (mean of 24 h GH profile) and erythrocyte electrolyte content as well as transmembrane sodium transport. The patients were reinvestigated two weeks after successful surgery (N=14) and again after one year (N=13). Erythrocyte electrolytes were analyzed by flame photometry and sodium influx and efflux rate constant determined by in vitro incubation using a modified Keyne's formula. In patients with active acromegaly there was a significant positive correlation between IGF-1 and cellular sodium transport, while GH tended to show a negative relationship to the same parameter. After successful treatment, both IGF-1 and GH disclosed a positive relationship to cellular sodium transport. After one year, a significant increase in erythrocyte sodium content was seen in the patients compared to the preoperative situation. In conclusion, if this is a generalized phenomenon the results are compatible with a sodium-retaining effect of GH via stimulation of transmembrane sodium transport. In active acromegaly this may be counteracted by a sodium transport inhibitor giving the reverse relationship between GH and cellular sodium transport.


1994 ◽  
Vol 131 (3) ◽  
pp. 313-318 ◽  
Author(s):  
Nisar A Pampori ◽  
Bernard H Shapiro

Pampori NA, Shapiro BH. Testicular regulation of sexual dimorphisms in the ultradian profiles of circulating growth hormone in the chicken. Eur J Endocrinol 1994;131:313–318. ISSN 0804–4643 Ultradian patterns in plasma growth hormone (GH) concentrations were determined in adult white Leghorn roosters, hens and capons. Serial blood samples were collected every 15 min over 8 h through surgically placed chronic indwelling right atrial catheters and assayed for GH content by a homologous radioimmunoassay. In both sexes, GH levels fluctuated episodically, with peak and interpeak periods each lasting about 45 min in both roosters and hens. However, GH concentrations in the peaks and nadirs were 2.5–3.5 times greater in the plasma GH profiles of roosters as compared to hens, which resulted in roosters having higher mean GH concentrations. Caponizing completely feminized the episodic GH secretory profile. In contrast to chickens, the common sexually dimorphic feature in secretory GH profiles of mammals is the enhanced peak frequencing found in females. Bernard H Shapiro, Laboratories of Biochemistry, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia, PA 19104-6048, USA


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