Thyrotropin-Releasing Hormone Stimulates Body Weight Gain and Increases Thyroid Hormones and Growth Hormone in Plasma of Cockerels

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.

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Induction of growth hormone (GH) mRNA by pulsatile GH-releasing hormone in rats is pattern specific

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.2000.278.5.e885 ◽

2000 ◽

Vol 278 (5) ◽

pp. E885-E891 ◽

Cited By ~ 4

Author(s):

Russell J. Borski ◽

Wellington Tsai ◽

Roberta Demott-Friberg ◽

Ariel L. Barkan

Keyword(s):

Growth Hormone ◽

Weight Gain ◽

Body Weight Gain ◽

Somatic Growth ◽

Pulse Amplitude ◽

Female Rats ◽

Mrna Levels ◽

Female Rat ◽

Constant Frequency ◽

Releasing Hormone

Growth hormone-releasing hormone (GHRH) is a main inducer of growth hormone (GH) pulses in most species studied to date. There is no information regarding the pattern of GHRH secretion as a regulator of GH gene expression. We investigated the roles of the parameters of exogenous GHRH administration (frequency, amplitude, and total amount) upon induction of pituitary GH mRNA, GH content, and somatic growth in the female rat. Continuous GHRH infusions were ineffective in altering GH mRNA levels, GH stores, or weight gain. Changing GHRH pulse amplitude between 4, 8, and 16 μg/kg at a constant frequency (Q3.0 h) was only moderately effective in augmenting GH mRNA levels, whereas the 8 μg/kg and 16 μg/kg dosages stimulated weight gain by as much as 60%. When given at a 1.5-h frequency, GHRH doubled the amount of GH mRNA, elevated pituitary GH stores, and stimulated body weight gain. In the rat model, pulsatile but not continuous GHRH administration is effective in inducing pituitary GH mRNA and GH content as well as somatic growth. These studies suggest that the greater growth rate, pituitary mRNA levels, and GH stores seen in male compared with female rats are likely mediated, in part, by the endogenous episodic GHRH secretory pattern present in males.

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Association of body weight gain with muscle, fat, and liver expression levels of growth hormone receptor, insulin-like growth factor I, and beta-adrenergic receptor mRNAs in steers

Domestic Animal Endocrinology ◽

10.1016/j.domaniend.2018.03.008 ◽

2018 ◽

Vol 64 ◽

pp. 31-37

Author(s):

W. Zheng ◽

X. Leng ◽

M. Vinsky ◽

C. Li ◽

H. Jiang

Keyword(s):

Growth Hormone ◽

Body Weight ◽

Weight Gain ◽

Growth Factor ◽

Hormone Receptor ◽

Adrenergic Receptor ◽

Growth Hormone Receptor ◽

Body Weight Gain ◽

Factor I ◽

Receptor Mrnas

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Development of obesity in transgenic rats with low circulating growth hormone levels: involvement of leptin resistance

Acta Endocrinologica ◽

10.1530/eje.0.1430535 ◽

2000 ◽

pp. 535-541 ◽

Cited By ~ 31

Author(s):

Y Furuhata ◽

R Kagaya ◽

K Hirabayashi ◽

A Ikeda ◽

KT Chang ◽

...

Keyword(s):

Growth Hormone ◽

Cerebrospinal Fluid ◽

Body Weight ◽

Weight Gain ◽

Locomotor Activity ◽

Food Intake ◽

Body Weight Gain ◽

Leptin Resistance ◽

Intracerebroventricular Injection ◽

Transgenic Rats

BACKGROUND: Human growth hormone (hGH) transgenic (TG) rats have been produced in our laboratory. These TG rats are characterized by low circulating hGH levels, virtually no endogenous rGH secretion, and massive obesity. OBJECTIVE: To elucidate how energy balance and leptin sensitivity contributed to the establishment of this obesity. DESIGN AND METHODS: Food intake, locomotor activity and leptin concentrations in serum and cerebrospinal fluid were measured in TG rats and their non-transgenic littermates (control). The effect of intraperitoneal and intracerebroventricular injection of leptin on food intake and body weight gain was also examined. RESULTS: An increase in food intake and a decrease in locomotor activity were observed from 4 and 7 weeks of age, respectively, in the transgenic rats compared with control. Serum leptin concentrations of the transgenic rats were more than twice as high as those of control rats and were associated with an increased white adipose tissue mass and ob gene expression. Intraperitoneal injection of leptin significantly decreased food intake and body weight gain in control rats, but not in transgenic rats. Leptin concentration in the cerebrospinal fluid of transgenic rats was not different from that of control rats, and intracerebroventricular injection of leptin was similarly effective in reducing food intake and body weight gain as it was in control rats. CONCLUSIONS: These results suggest that the transgenic rats, whose GH secretion is suppressed, develop obesity due to early onset of an increase in food intake and a decrease in locomotor activity with leptin resistance resulting from deteriorating leptin transport from peripheral blood to cerebrospinal fluid.

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