The role of thyroid hormones in the growth hormone response to protein restriction in the domestic fowl (Gallus domesticus)

1988 ◽  
Vol 117 (2) ◽  
pp. 223-228 ◽  
Author(s):  
T. J. Lauterio ◽  
C. G. Scanes
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Plasma Concentrations ◽  
Hormone Response ◽  
Gh Secretion ◽  
Low Protein ◽  
Increased Sensitivity ◽  
Plasma Gh ◽  
Protein Diets

ABSTRACT The possible role of thyroid hormones in the rise in plasma GH observed in protein-restricted chicks was examined. Increased sensitivity of protein-restricted chicks to secretagogue challenge (TRH or GH-releasing factor) appears to account, at least in part, for increased GH concentrations in protein-restricted chicks. Thyroid hormones administered acutely were able to suppress plasma GH concentrations in protein-restricted chicks. Further, chronic thyroid hormone supplementation to low protein diets normalized circulating thyroid hormone concentrations and also normalized the response to GH secretagogue challenge. This decreased sensitivity to TRH provocation occurred without an accompanying change in plasma concentrations of insulin-like growth factor-I, a reputed inhibitor of GH secretion in the chicken. J. Endocr. (1988) 117, 223–228

scholarly journals Unravelling the role of thyroid hormones in seasonal neuroplasticity in European Starlings (Sturnus vulgaris)

2021 ◽  
Author(s):  
Jasmien EMJ Orije ◽  
Sander R Raymaekers ◽  
Gaurav Majumadar ◽  
Geert De Groof ◽  
Elisabeth Jonckers ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Plasma Concentrations ◽  
Active Role ◽  
Fine Tuning ◽  
European Starlings ◽  
Photosensitive Period ◽  
Song Control

Thyroid hormones clearly play a role in the seasonal regulation of reproduction, but any role they might play in song behavior and the associated seasonal neuroplasticity in songbirds remains to be elucidated. To pursue this question, we first established seasonal patterns in the expression of thyroid hormone regulating genes in male European starlings employing in situ hybridization methods. Thyroid hormone transporter LAT1 expression in the song nucleus HVC was elevated during the photosensitive phase, pointing towards an active role of thyroid hormones during this window of possible neuroplasticity. In contrast, DIO3 expression was high in HVC during the photostimulated phase, limiting the possible effect of thyroid hormones to maintain song stability during the breeding season. Next, we studied the effect of hypothyroidism on song behavior and neuroplasticity using in vivo MRI. Hypothyroidism inhibited the photostimulation-induced increase in testosterone, confirming the role of thyroid hormones in activating the hypothalamic-pituitary-gonadal (HPG) axis. Surprisingly, apart from the myelination of several tracts during the photostimulated phase, most neuroplasticity related to song production was unaffected by hypothyroidism. Remarkably, T3 plasma concentrations were negatively correlated to the microstructural changes in several song control nuclei. Potentially, a global reduction of circulating thyroid hormones during the photosensitive period is necessary to lift the brake imposed by the photorefractory period, whereas local fine-tuning of thyroid hormone concentrations through LAT1 could activate underlying neuroplasticity mechanisms. Given the complexity of thyroid hormone effects, this study is a steppingstone to disentangle the influence of thyroid hormones on seasonal neuroplasticity.

scholarly journals Role of reduced thyroid hormone status on bone mineral metabolism

2021 ◽  
Vol 19 (2) ◽  
pp. 26-29
Author(s):  
X Lourdes Sandy ◽  
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Bone Mineral ◽  
Serum Calcium ◽  
Mineral Metabolism ◽  
Bone Mineral Metabolism ◽  
Hormone Status ◽  
Calcium And Phosphorus ◽  
Hypothyroid Patients

Background: The most common endocrine disorder is hypothyroidism which accounts to 11%. Thyroid hormones have a wide array of functions such as physiological growth and development of skeletal system, maintenance of basal metabolic rate and regulation of various metabolisms, including mineral metabolism. Nowadays due to its direct action on bone turn over, thyroid hormones are considered to have an important role on bone mineral metabolism. Thyroid disorders are important cause for secondary osteoporosis. So the present study was done to know the levels of bone minerals, calcium and phosphorus in hypothyroidism and its relation with thyroid hormone levels. Methods: A case-control study was conducted on 30 hypothyroid patients and 30 euthyroid healthy controls in the age group of 20-60 years. Blood samples were collected from all the study population. Serum total triiodothyronine, total thyroxine and TSH by Enzyme-Linked Immunosorbent Assay, Serum calcium by Arsenazo III method, phosphorous by ammonium molybdate method were estimated. Results: Serum calcium levels in cases was found to significantly reduced when compared to controls (p<0.001). Serum phosphorous levels also showed considerable elevation in cases when compared to controls (p<0.001). There was a significant negative correlation between TSH and serum calcium in cases. Conclusion: The present study indicated the important role of reduced thyroid hormone status on bone mineral metabolism. This study concludes that serum calcium was significantly reduced and phosphorus levels were significantly increased in hypothyroid patients when compared to euthyroid control subjects. So frequent monitoring of serum calcium and phosphorus in hypothyroid patients would reduce the burden of bone pathologies.

Milk Protein Quantity and Quality in Low-Birth-Weight Infants: II. Effects on Selected Aliphatic Amino Acids in Plasma and Urine

PEDIATRICS ◽  
1977 ◽  
Vol 59 (3) ◽  
pp. 407-422 ◽  
Author(s):  
David K. Rassin ◽  
Gerald E. Gaull ◽  
Kirsti Heinonen ◽  
Niels C. R. Räihäa
Keyword(s):  
Amino Acids ◽  
Birth Weight ◽  
Low Birth Weight ◽  
Human Milk ◽  
Free Amino Acids ◽  
Free Amino ◽  
Plasma Concentrations ◽  
Low Birth Weight Infants ◽  
Low Protein ◽  
Protein Diets

The optimal quantity and quality of protein for low-birth-weight infants is undefined. In this study, 106 well, appropriate-for-gestational-age, low-birth-weight infants weighing 2,100 gm or less were divided into three gestational age groups and assigned randomly within each age group to one of five feeding regimens: pooled human milk; formula 1 (protein content, 1.5 gm/100 ml, 60 parts bovine whey proteins to 40 parts bovine caseins); formula 2 (3.0 gm/100 ml, 60:40); formula 3 (1.5 gm/100 ml, 18:82); and formula 4 (3.0 gm/100 ml, 18:82). The concentrations of the free amino acids in the plasma and urine of these infants were determined. The plasma concentrations of free amino acids were generally far greater in the infants fed the 3.0-gm/100 ml protein diets than they were in the infants fed pooled human milk. The plasma concentrations of free amino acids of the infants fed the 1.5-gm/100 ml protein diets were intermediate. In general, the concentrations of the free amino acids in the plasma of the infants fed the 3.0-gm/100 ml caseinpredominant formula (F4) were furthest from those fed pooled human milk. Glutamate showed the highest plasma amino acid concentrations in infants fed both the high- and low-protein casein-predominant formulas. This was true despite the fact that the intake of glutamate on the high-protein, whey-predominant formula was twice that on the low-protein, casein-predominant formula. The differences between groups in the essential amino acids in plasma were generally greater than those of the nonessential amino acids. The concentrations of amino acids in the urine tended to parallel those of the plasma.

Thyroid hormone concentrations in the plasma of fed and fasted Brahman and Hereford steers

1994 ◽  
Vol 34 (4) ◽  
pp. 439
Author(s):  
JC O'Kelly ◽  
WG Spiers
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Plasma Concentrations ◽  
Free T4 ◽  
Rumen Metabolism ◽  
Body Tissues ◽  
Breed Differences ◽  
Feeding Regimes ◽  
Ad Libitum ◽  
Brahman Steers

Plasma concentration patterns of thyroxine (TJ, free T4 (FT4), triiodothyronine (T3), and free T3 (FT3) were determined in Brahman steers fed lucerne hay ad libitum and in Brahman and Hereford steers fed restricted intakes of lucerne hay at the rate of either 208 g/h before fasting for 72 h or 250 g/h before fasting for 96 h. In Brahmans fed ad libitum, the plasma concentrations of all thyroid hormone fractions were significantly (P<0.01) correlated with one another and with feed intake. Within breeds, the concentrations of thyroid hormones were higher (P<0.001) when animals were fed at 250 g k than at 208 g/h. During both hourly feeding regimes T4, FT4, T3, and FT3 concentrations were higher (P<0.001) in Brahmans than in Herefords. Fasting after both hourly feeding regimes lowered (P<0.001) the concentrations of T4 about 53% in Brahmans and 30% in Herefords, while FT4, T3, and FT3 were lowered about 68% in Brahmans and 50% in Herefords. Consequently, thyroid hormone concentrations were significantly lower in Brahmans than in Herefords after 72 h fasting but did not differ significantly between breeds after 96 h fasting. The present results, together with those of our previous work showing breed differences in rumen metabolism, support the concept that, in Hereford and Brahman steers fed the same amount of hay in a thermoneutral environment, breed differences in plasma concentrations of thyroid hormones originate from quantitative differences in the supply of nutrients from the rumen to body tissues.

scholarly journals Possible role of available phosphorus in potentiating the use of low-protein diets for broiler chicken production

2020 ◽  
Vol 99 (12) ◽  
pp. 6954-6963
Author(s):  
A.J. Cowieson ◽  
R. Perez-Maldonado ◽  
A. Kumar ◽  
M. Toghyani
Keyword(s):  
Broiler Chicken ◽  
Available Phosphorus ◽  
Low Protein ◽  
Protein Diets

Somatotrophic and thyroid hormones around the onset of lay in broiler breeders under different conditions

2002 ◽  
Vol 50 (4) ◽  
pp. 425-434
Author(s):  
R. D. Malheiros ◽  
Vera Maria Barbosa Moraes ◽  
R. L. Furlan ◽  
Keyword(s):  
Thyroid Hormones ◽  
Cell Function ◽  
High Plasma ◽  
Significant Rise ◽  
Broiler Breeders ◽  
Housing Systems ◽  
Gh Secretion ◽  
Age Related ◽  
Group A ◽  
Plasma Gh

Somatotrophic and thyroid hormones were determined around the onset of reproduction in broiler breeders reared in two different housing systems [dark, close-sided house (CH) and conventional, open-sided house (OH)]. In both groups age-related changes were obvious for thyroxine (T4), growth hormone (GH) and insulin-like growth factor (IGF-1); levels of T4 decreased, especially between 24 and 28 weeks in both groups; concomitantly GH sharply increased over the same period. A transient peak in triiodothyronine (T3) occurred between 25 and 27 weeks. The effect of housing was only present after the onset of lay. Between weeks 27-28 and the end of the period studied, the CH group showed higher levels of GH and T3 but lower T4 levels as compared to the OH group. A significant increase in GH after onset of lay, without any significant rise in T3 or in IGF-I, could point to a relative insensitivity to high plasma GH levels. Changes at GH receptor level, together with an increased pituitary GH secretion and/or decreased GH turnover may be expected. This may indicate that hypothalamo-pituitary changes at the onset of lay not only imply changes of gonadotrophic cell function, but also other hormonal axes. The relatively decrease in T4 without changes in T3, may point to a decrease in the activity of the thyrotropic axis.

Effect of actively immunizing sheep against growth hormone-releasing hormone or somatostatin on spontaneous pulsatile and neostigmine-induced growth hormone secretion

1995 ◽  
Vol 144 (1) ◽  
pp. 83-90 ◽  
Author(s):  
E Magnan ◽  
L Mazzocchi ◽  
M Cataldi ◽  
V Guillaume ◽  
A Dutour ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Body Weight ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Physiological Role ◽  
Gh Secretion ◽  
Igf I ◽  
Plasma Gh ◽  
Hypophysial Portal

Abstract The physiological role of endogenous circulating GHreleasing hormone (GHRH) and somatostatin (SRIH) on spontaneous pulsatile and neostigmine-induced secretion of GH was investigated in adult rams actively immunized against each neuropeptide. All animals developed antibodies at concentrations sufficient for immunoneutralization of GHRH and SRIH levels in hypophysial portal blood. In the anti GHRH group, plasma GH levels were very low; the amplitude of GH pulses was strikingly reduced, although their number was unchanged. No stimulation of GH release was observed after neostigmine administration. The reduction of GH secretion was associated with a decreased body weight and a significant reduction in plasma IGF-I concentration. In the antiSRIH group, no changes in basal and pulsatile GH secretion or the GH response to neostigmine were observed as compared to controls. Body weight was not significantly altered and plasma IGF-I levels were reduced in these animals. These results suggest that in sheep, circulating SRIH (in the systemic and hypophysial portal vasculature) does not play a significant role in pulsatile and neostigmine-induced secretion of GH. The mechanisms of its influence on body weight and production of IGF-I remain to be determined. Journal of Endocrinology (1995) 144, 83–90

Secretion of growth hormone-releasing hormone in patients with idiopathic pituitary dwarfism and acromegaly

1988 ◽  
Vol 117 (2) ◽  
pp. 273-281 ◽  
Author(s):  
Ryuichi Yamasaki ◽  
Haruhiko Saito ◽  
Kazuhito Kameyama ◽  
Eiji Hosoi ◽  
Shiro Saito
Keyword(s):  
Type I ◽  
Normal Children ◽  
Pituitary Dwarfism ◽  
Gh Secretion ◽  
Fasting Plasma ◽  
Pathophysiological Role ◽  
Plasma Gh ◽  
High Level ◽  
Normal Adults

Abstract. The plasma levels of immunoreactive-GHRH in patients with idiopathic pituitary dwarfism and acromegaly were studied in the basal state and during various tests by a sensitive and specific RIA. The fasting plasma GHRH level in 22 patients with idiopathic pituitary dwarfism was 6.3 ± 2.3 ng/l (mean ± sd), which was significantly lower than that in normal children (9.8 ± 2.8 ng/l, N = 21), and eight of them had undetectable concentrations (less than 4.0 ng/l). Little or no response of plasma GHRH to oral administration of L-dopa was observed in 7 of 10 pituitary dwarfs, and 3 of the 7 patients showed a response of plasma GH to iv administration of GHRH (1 μg/kg). These findings suggest that one of the causes of idiopathic pituitary dwarfism is insufficient GHRH release from the hypothalamus. The fasting plasma GHRH level in 14 patients with acromegaly and one patient with gigantism was 8.0 ± 3.9 ng/l, which was slightly lower than that in normal adults (10.4 ± 4.1 ng/l, N = 72). One acromegalic patient with multiple endocrine neoplasia type I had a high level of plasma GHRH (270 ng/l) with no change in response to L-dopa and TRH test. In 3 untreated patients with acromegaly L-dopa did not induce any response of plasma GHRH in spite of inconsistent GH release, and in 4 patients with acromegaly, TRH evoked no response of plasma GHRH in spite of a marked GH release, suggesting that the GH responses are not mediated by hypothalamic GHRH. These findings suggest that the measurement of plasma GHRH in response to L-dopa with a sensitive and specific RIA could be of use in clarifying the pathophysiological role of endogenous GHRH in patients with GH secretion disorders.

Effects of hysterectomy and in-vivo treatment with uterine extracts on plasma concentrations of growth hormone, thyrotrophin and thyroid hormones in rats: a kinetic study

1984 ◽  
Vol 101 (3) ◽  
pp. 243-248 ◽  
Author(s):  
J. Bíró ◽  
P. Eneroth ◽  
E. M. Ritzén
Keyword(s):  
Growth Hormone ◽  
Thyroid Hormones ◽  
Kinetic Study ◽  
Plasma Concentrations ◽  
Adult Rats ◽  
In Vivo Treatment ◽  
Plasma Gh

ABSTRACT Plasma concentrations of GH, TSH, tri-iodothyronine (T3) and thyroxine (T4) were measured in adult rats 2 and 4 weeks after ovariectomy and ovariohysterectomy. Two weeks after ovariohysterectomy, the concentration of GH was significantly higher, but TSH and T3 concentrations were significantly lower than in rats which had been ovariectomized only. Hysterectomy had no effect on plasma GH and TSH concentrations if it was performed 2 weeks after ovariectomy. Plasma T3 had decreased by 2 weeks after ovariectomy but returned to pretreatment levels by 4 weeks. Recovery of the plasma T3 concentration was not observed if ovariectomy was followed by hysterectomy, since a further decrease of plasma T3 occurred. Plasma T4 was not significantly influenced either by ovariectomy or by ovariohysterectomy. Steroid-free uterine extracts given i.p. to ovariohysterectomized rats reduced plasma GH within 24 h of injection. Increases in plasma TSH, T3 and T4 were achieved in ovariohysterectomized rats with injections of uterine extracts (from intact, oestrogen-treated or castrated rats), but the increases were not consistent for the three hormones either as regards time after injection, nor for which particular extracts were effective. It was concluded that the uterus may contain factors which influence the GH storage and secretion and TSH-thyroid regulation in rats. J. Endocr. (1984) 101, 243–248

scholarly journals THE ROLE OF HOMOCYSTINE IN PROTECTING PROTEIN-DEPLETED DOGS EXPOSED TO FATAL DOSES OF CHLOROFORM

1955 ◽  
Vol 101 (2) ◽  
pp. 197-204
Author(s):  
George P. Vennart ◽  
Frank W. McKee
Keyword(s):  
Liver Damage ◽  
Methyl Groups ◽  
Histological Changes ◽  
Long Period ◽  
Lethal Action ◽  
Low Protein ◽  
Depletion Period ◽  
Protein Diets ◽  
Cellular Destruction

In dogs maintained on low protein diets and subjected to phlebotomy over a long period of time, the inhalation of chloroform, for 30 minutes, produced uniform fatality within 48 hours. The histological changes of massive hepato-cellular destruction were observed at autopsy. Homocystine, in the amount of 2.0 gm., given orally 2 hours after or 2 hours prior to the administration of chloroform, protected dogs against the lethal action of the toxin. Inconstant changes in fibrinogen and icteric indices were observed in the protected animals, indicating some mild liver damage, but this was not correlated with the length of the previous depletion period, the phase of the experiment, or any other factor. No evidence was obtained that methyl groups are necessary for the protection of the liver by homocystine.

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