Seasonal changes in weight gain, growth hormone, and thyroid hormones in intact and castrated male moose (Alces alces alces)

1982 ◽  
Vol 60 (11) ◽  
pp. 2941-2946 ◽  
Author(s):  
Morten Ryg
Keyword(s):  
Growth Hormone ◽  
Weight Gain ◽  
Thyroid Hormone ◽  
Food Intake ◽  
Thyroid Hormones ◽  
Seasonal Changes ◽  
Alces Alces ◽  
Serum Concentrations ◽  
Rapid Weight Gain ◽  
Thyroid Hormone Levels

To elucidate possible endocrine mechanisms in the control of cyclic weight gain in moose, serum concentrations of growth hormone (GH), thyroxine (T4), and triiodothyronine (T3) were recorded during the year in two intact and one castrated male moose. Changes in the levels of these hormones were compared with changes in weight gain. Growth hormone often increased to peak values in April or May, but was generally low throughout the period of greatest weight gain. Thyroid hormone levels increased in spring and decreased in autumn, corresponding to onset and cessation of rapid weight gain. Changes in triiodothyronine levels may have been secondary to changes in food intake.

Seasonal changes in weight gain, growth hormone, and thyroid hormones in male red deer (Cervus elaphus atlanticus)

1982 ◽  
Vol 60 (11) ◽  
pp. 2577-2581 ◽  
Author(s):  
Morten Ryg ◽  
Rolf Langvatn
Keyword(s):  
Growth Hormone ◽  
Weight Gain ◽  
Food Intake ◽  
Thyroid Hormones ◽  
Cervus Elaphus ◽  
Seasonal Changes ◽  
Red Deer ◽  
Antler Growth ◽  
Gain Peak

To elucidate possible endocrine mechanisms in the control of the weight cycle of red deer, we recorded seasonal changes in the concentrations of growth hormone (GH), thyroxine (T4), and triiodothyronine (T3) in serum. T3 and T4 were analyzed with specific radioimmunoassays, GH was analyzed with a hetereologous radioimmunoassay. Changes in the levels of these hormones were compared with changes in weight gain. T3 levels were high in summer and low in winter, corresponding to changes in weight gain. Peak values (1.75–4.82 nmol/L) were found in May or June, nadirs occurred in April (0.22–1.78 nmol/L) or October–November (0–1.19 nmol/L). GH levels increased to peak values, 20–53 ng/mL, in April to June, but were low during most of the period of fast weight gain. There were no consistent changes in T4 levels corresponding to the weight cycle. We conclude that the GH peaks following the casting of old antlers may be related to the onset of antler growth. Seasonal changes in T3 levels may be secondary to changes in food intake.

Effects of methimazole treatment on growth hormone (GH) response to GH-releasing hormone in patients with hyperthyroidism

1990 ◽  
Vol 123 (6) ◽  
pp. 613-618 ◽  
Author(s):  
Andrea Giustina ◽  
Carlo Ferrari ◽  
Corrado Bodini ◽  
Maria Grazia Buffoli ◽  
Fabio Legati ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Pituitary Cells ◽  
Hormone Levels ◽  
Gh Secretion ◽  
Thyroid Hormone Levels ◽  
Ghrh Test ◽  
Hyperthyroid Patients

Abstract. In vitro studies have demonstrated that thyroid hormones can enhance basal and stimulated growth hormone secretion by cultured pituitary cells. However, both in man and in the rat the effects of high thyroid hormone levels on GH secretion are unclear. The aim of our study was to test the GH response to human GHRH in hyperthyroid patients and to evaluate the effects on GH secretion of short- and long-term pharmacological decrease of circulating thyroid hormones. We examined 10 hyperthyroid patients with recent diagnosis of Graves' disease. Twelve healthy volunteers served as controls. All subjects received a bolus iv injection of GHRH(1-29)NH2, 100 μg. Hyperthyroid patients underwent a GHRH test one and three months after starting antithyroid therapy with methimazole, 10 mg/day po. GH levels at 15, 30, 45, 60 min and GH peak after stimulus were significantly lower in hyperthyroid patients than in normal subjects. The GH peak was also delayed in hyperthyroid patients. After one month of methimazole therapy, most of the hyperthyroid patients had thyroid hormone levels in the normal range, but they did not show significant changes in GH levels after GHRH, and the GH peak was again delayed. After three months of therapy with methimazole, the hyperthyroid patients did not show a further significant decrease in serum thyroid hormone levels. However, mean GH levels from 15 to 60 min were significantly increased compared with the control study. The GH peak after GHRH was also earlier than in the pretreatment study. In conclusion, the GH response to GHRH is inhibited and delayed by hyperthyroidism and returns to the normal pattern after long-term euthyroidism has been achieved with methimazole.

Effects of thyroid hormones and prolactin on food intake and weight changes in young male reindeer (Rangifer tarandus tarandus)

1982 ◽  
Vol 60 (7) ◽  
pp. 1562-1567 ◽  
Author(s):  
Morten Ryg ◽  
Endre Jacobsen
Keyword(s):  
Weight Gain ◽  
Thyroid Hormone ◽  
Food Intake ◽  
Thyroid Hormones ◽  
Rangifer Tarandus ◽  
Hormone Secretion ◽  
Young Male ◽  
Growth Cycle ◽  
Prolactin Secretion ◽  
Weight Changes

Yearling male reindeer were treated with thyroid hormones and prolactin to see if reported seasonal variations in these hormones could participate in the control of the growth cycle in Cervidae. Both prolactin and thyroid hormone injections were followed by increased food intake. The effect was not additive, and no interactions were seen. Weight gain decreased after treatment with thyroid hormone, alone or in combination with prolactin. Weight gain increased in animals treated with prolactin alone. We conclude that changes in prolactin secretion may be important for the regulation of the growth cycle, but that the role of changes in thyroid hormone secretion is unclear.

scholarly journals Neuropeptide Y1 and Y5 Receptors Mediate the Effects of Neuropeptide Y on the Hypothalamic-Pituitary-Thyroid Axis

Endocrinology ◽  
2002 ◽  
Vol 143 (12) ◽  
pp. 4513-4519 ◽  
Author(s):  
Csaba Fekete ◽  
Sumit Sarkar ◽  
William M. Rand ◽  
John W. Harney ◽  
Charles H. Emerson ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Food Intake ◽  
Neuropeptide Y ◽  
Paraventricular Nucleus ◽  
Receptor Agonist ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
Ad Libitum ◽  
Thyroid Hormone Levels ◽  
Hpt Axis

Abstract Neuropeptide Y (NPY) is one of the most important hypothalamic-derived neuropeptides mediating the effects of leptin on energy homeostasis. Central administration of NPY not only markedly stimulates food intake, but simultaneously inhibits the hypothalamic-pituitary-thyroid axis (HPT axis), replicating the central hypothyroid state associated with fasting. To identify the specific NPY receptor subtypes involved in the action of NPY on the HPT axis, we studied the effects of the highly selective Y1 ([Phe7,Pro34]pNPY) and Y5 ([chicken pancreatic polypeptide1–7, NPY19–23, Ala31, Aib32 (aminoisobutyric acid), Q34]human pancreatic polypeptide) receptor agonists on circulating thyroid hormone levels and proTRH mRNA in hypophysiotropic neurons of the hypothalamic paraventricular nucleus. The peptides were administered continuously by osmotic minipump into the cerebrospinal fluid (CSF) over 3 d in ad libitum-fed animals and animals pair-fed to artificial CSF (aCSF)-infused controls. Both Y1 and Y5 receptor agonists nearly doubled food intake compared with that of control animals receiving aCSF, similar to the effect observed for NPY. NPY, Y1, and Y5 receptor agonist administration suppressed circulating levels of thyroid hormones (T3 and T4) and resulted in inappropriately normal or low TSH levels. These alterations were also associated with significant suppression of proTRH mRNA in the paraventricular nucleus, particularly in the Y1 receptor agonist-infused group [aCSF, NPY, Y1, and Y5 (density units ± sem), 97.2 ± 8.6, 39.6 ± 8.4, 19.9 ± 1.9, and 44.6 ± 8.4]. No significant differences in thyroid hormone levels, TSH, or proTRH mRNA were observed between the agonist-infused FSanimals eating ad libitum and the agonist-infused animals pair-fed with vehicle-treated controls. These data confirm the importance of both Y1 and Y5 receptors in the NPY-mediated increase in food consumption and demonstrate that both Y1 and Y5 receptors can mediate the inhibitory effects of NPY on the HPT axis.

Seasonal changes in serum thyroid hormone levels in ruffed grouse maintained under natural conditions of temperature and photoperiod

1979 ◽  
Vol 57 (10) ◽  
pp. 2022-2027 ◽  
Author(s):  
A. Garbutt ◽  
J. F. Leatherland ◽  
A. L. A. Middleton
Keyword(s):  
Thyroid Hormone ◽  
Seasonal Changes ◽  
Gonadal Development ◽  
Early Spring ◽  
Light Period ◽  
Ruffed Grouse ◽  
Natural Conditions ◽  
Blood Samples ◽  
Serum Thyroid Hormone ◽  
Thyroid Hormone Levels

Serum triiodothyronine (T3) and thyroxine (T4) concentrations were measured in a population of ruffed grouse, held outdoors under natural conditions of photoperiod and temperature. Blood samples were collected at monthly intervals, and at the solstices and equinoxes to test for variation through the light period. No changes in T4 or T3 levels were found during the light period but levels of T3 and T4 showed marked seasonal changes. Lowest T4 and T3 levels were found in birds during the winter months, with an increase in the concentration of both hormones in early spring concomitant with gonadal development in the adults. A lowering of serum T4 and T3 values was associated with the period of molt.

Stimulation of food intake and weight gain in mature female rats by bovine prolactin and bovine growth hormone

1993 ◽  
Vol 264 (6) ◽  
pp. E986-E992 ◽  
Author(s):  
J. C. Byatt ◽  
N. R. Staten ◽  
W. J. Salsgiver ◽  
J. G. Kostelc ◽  
R. J. Collier
Keyword(s):  
Growth Hormone ◽  
Body Weight ◽  
Weight Gain ◽  
Food Intake ◽  
Body Weight Gain ◽  
Mature Female ◽  
Female Rats ◽  
Bovine Growth Hormone ◽  
Female Rat ◽  
Moisture Percentage

Recombinant bovine prolactin (rbPRL) or bovine growth hormone (rbGH) was administered to mature female rats (10/treatment group) by daily subcutaneous injection for 10 days. Doses ranged from 7 to 5,000 micrograms/day (0.03-24 mg/kg body wt). Both rbPRL and rbGH increased body weight gain and food intake, but these parameters were increased at lower doses of rbPRL (7-63 micrograms/day) than rbGH (> 190 micrograms/day). Weight gain and food intake were maximally stimulated by 190 micrograms/day rbPRL, whereas maximal increased weight gain was obtained with the highest dose of rbGH (5,000 micrograms/day). Total carcass protein was increased by both hormones; however, protein as a percentage of body weight was unchanged. Similarly, neither rbPRL nor rbGH changed the percentage of carcass moisture. Percentage of body fat was increased by rbPRL but was decreased by rbGH. Weight of the gastrointestinal tract and kidneys was increased by both hormones, but increases were in proportion to body weight gain. These data confirm that ungulate prolactin is a hyperphagic agent in the female rat. In addition, they suggest that, while prolactin stimulates growth in mature female rats, this growth is probably not via a somatogenic mechanism.

Pathophysiology and management of functional endocrine tumours in the critically ill

2016 ◽  
Author(s):  
Sara Nikravan ◽  
Frederick Mihm
Keyword(s):  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Diagnostic Tests ◽  
Concurrent Treatment ◽  
Peripheral Tissues ◽  
Endocrine Tumours ◽  
Optimal Dosing ◽  
Serum Thyroid Hormone ◽  
Thyroid Hormone Levels ◽  
T3 Receptors

Thyroid hormones act on most tissues via nuclear T3 receptors. Thyroid hormones stimulate oxygen consumption and heat production, influence cell growth and maturation (central nervous system, bone), and modulate metabolism (carbohydrates, lipids, proteins, drugs). Treatment for presumed thyroid disease frequently has to be initiated before the results of diagnostic tests are available. Treatment of hyperthyroidism should result in the reduction of serum thyroid hormone levels and their action on peripheral tissues with concurrent treatment of the precipitating event. In severe hypothyroidism the choice of thyroid hormone (thyroxine or tri-iodothyronine), optimal dosing, and the route of administration remain controversial

Physiological and behavioral responses to starvation in the golden hamster.

1979 ◽  
Vol 236 (2) ◽  
pp. E105 ◽  
Author(s):  
K T Borer ◽  
N Rowland ◽  
A Mirow ◽  
R C Borer ◽  
R P Kelch
Keyword(s):  
Fatty Acids ◽  
Weight Loss ◽  
Weight Gain ◽  
Food Intake ◽  
Behavioral Responses ◽  
Blood Metabolites ◽  
Serum Concentrations ◽  
Weight Losses ◽  
Beta Hydroxybutyrate ◽  
Access To Food

Physiological and behavioral responses of adult hamsters to starvation were studied by measuring food intake, weight recovery, serum concentrations of glucose, insulin, free fatty acids and beta-hydroxybutyrate, and ketonuria in animals subjected to different weight losses, diets, and durations of fast. Hamsters were debilitated by fasts longer than 12 h or leading to greater than 20% weight loss. Hamsters' feeding patterns were unmodified by fasts ranging between 5 and 12 h and showed no circadian periodicity. Hamsters predominantly recovered from weight losses without increasing their food consumption (unless they were offered a diet of pellets and seeds) and without changing their meal patterns, at a rate of weight gain proportional to the magnitude of preceding weight loss if provided with uninterrupted access to food. By 8 h of fast, blood metabolites were indicative of mobilization of body fat. Hamsters are thus behaviorally unresponsive to duration of fast, but compensate physiologically for weight losses with proportional increases in the rate of weight gain.

Hypothyroidism does not affect the dihydropyridine sensitivity of precontracted murine uterus

2003 ◽  
Vol 81 (9) ◽  
pp. 890-893 ◽  
Author(s):  
Jörg W Wegener ◽  
Matthias Lee ◽  
Franz Hofmann
Keyword(s):  
Smooth Muscle ◽  
Cell Differentiation ◽  
Thyroid Hormone ◽  
Thyroid Hormones ◽  
Rat Uterus ◽  
Hormone Levels ◽  
Uterine Muscle ◽  
Channel Expression ◽  
Thyroid Hormone Levels ◽  
Pregnant State

Thyroid hormones are known to influence various processes of cell differentiation. Recently, it was reported that hypothyroidism reduces the sensitivity to Ca2+-channel antagonists in the rat uterus. We examined the sensitivity to dihydropyridines of the uterus from mice that had reduced thyroid hormone levels. Isradipine relaxed with the same potency precontracted uterine muscle strips from control and hypothyroid mice, independently from a pseudo-pregnant state. These results demonstrate that hypothyroidism does not change dihydropyridine sensitivity (i.e., the pattern of Ca2+-channel expression) in the murine uterus.Key words: uterus, smooth muscle, Ca2+ channel, isradipine.

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