Growth Hormone and Prolactin Secretion in Genetically Obese Zucker Rats*

Finkelstein, James D.; Jervois, P.M.; Menadue, Margaret; Willoughby, John O.

doi:10.1210/endo-118-3-1233

Cited by 54 publications

(26 citation statements)

References 18 publications

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“…1, 2). While no significant difference in tail length was seen between groups receiving GH treatment or saline, as reported by Finkelstein et al [22], tail automutilation was sometimes observed in KK-A y obese mice with GH treatment, as in monosodium L-glutamatetreated obese mice [23]. Consequently, the Lee index, reflecting percent body fat, continued to fall markedly from 55 days old to the final point in contrast to Controls, despite increased body weight (Fig.…”

Section: Discussionsupporting

confidence: 65%

Growth Hormone Administration Controls Body Composition Associated with Changes of Thermogenesis in Obese KK-Ay Mice~!2009-08-29~!2010-01-12~!2010-03-26~!

Hioki¹,

Yoshida²,

Kogure³

et al. 2010

TOEJ

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Abstract:We investigate the effects of continuous human growth hormone (GH) therapy in young obese mice on thermogenesis. Female KK-A y obese mice (n=10) were injected subcutaneously with GH (3.5 mg/kg/day) for 30 days from 42 days old. As a control, physiological saline was administered (n=10). At the terminal point (71 days old), GH administration affected linear growth, and the Lee obesity index (3 square root body weight/nasoanal length 1000) was significantly decreased. Rates of inguinal and perimetric white adipose pads per body weight also decreased. Free fatty acid levels decreased, while plasma insulin concentrations and homeostasis model assessment insulin resistance were increased (P<0.01). Plasma insulin-like growth factor (IGF-1) levels markedly rose (P<0.00001). Uncoupling protein1 (UCP1) and UCP3 mRNA expressions in brown adipose tissue were inhibited (P<0.05). Continuous GH therapy changed obese body composition toward lean, however, the consequence could be the negative regulation of thermogenesis.

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Section: Discussionsupporting

confidence: 65%

Growth Hormone Administration Controls Body Composition Associated with Changes of Thermogenesis in Obese KK-Ay Mice~!2009-08-29~!2010-01-12~!2010-03-26~!

Hioki¹,

Yoshida²,

Kogure³

et al. 2010

TOEJ

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“…Conscious of the limitations derived from the analysis of only one sample of serum GH, we chose for our purpose animals of two ages where the degree of GH deficiency in obese rats is well established. Thus, it has been demonstrated that plasma levels of GH, pulsatile GH release, pituitary GH concentration, and mRNA expression are reduced in obese male rats when compared with lean littermates, and that this defect is maximal at 10-12 weeks of age (Finkelstein et al 1986, Ahmad et al 1990, Tannenbaum et al 1990, Leidy et al 1993.…”

Section: Discussionmentioning

confidence: 99%

Tissue-specific response of IGF-I mRNA expression to obesity-associated GH decline in the male Zucker fatty rat

Melián

Gonzalez²,

Ajo³

et al. 1999

Journal of Endocrinology

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Diminished GH secretion is a well known association of obesity. As in obese humans, Zucker fatty rats develop a progressive GH deficiency, present at 6 weeks of age and maximal at 10 to 12 weeks. The aim of this study was to investigate the GH dependence of IGF-I gene expression in liver and extrahepatic tissues of the obese Zucker rat as a model of progressive GH reduction during adult life. Six-and 11-week-old obese Zucker rats and their lean littermates were used to compare body weight, glycemia, insulinemia, serum GH and IGF-I levels and IGF-I mRNA expression in liver, heart, aorta, kidney and skeletal muscle. In comparison with lean controls, obese Zucker rats showed at both ages comparable glycemia, severe hyperinsulinemia (mU/ml, mean ...; 6 weeks 138 10 vs 45 6 P<0·001; 11 weeks 147 14 vs 46 3, P<0·001) and lower GH (ng/ml; 6 weeks 1·7 0·9 vs 2·7 1·1; 11 weeks 1·5 0·9 vs 4·2 1·2) in the presence of similar circulating IGF-I levels (ng/ml; 6 weeks 774 26 vs 694 28; 11 weeks 1439 182 vs 1516 121). Hepatic IGF-I mRNA expression was already reduced at 6 weeks of age due to a significant decrease in the IGF-Ib transcript compared with lean controls (relative units; IGF-Ia: 99 2% vs 100 5%; IGF-Ib: 69 10% vs 100 2%, P<0·05) and this reduction was more marked in 11-week-old animals when both IGF-I transcripts were significantly diminished (relative units; IGF-Ia: 80 6% vs 100 1%, P<0·05; IGF-Ib: 65 5% vs 100 2%, P<0·01). Extrahepatic tissues expressed almost exclusively the IGF-Ia transcript, the amount of which relative to controls was: (1) similar at 6 weeks and decreased at 11 weeks in kidney and skeletal muscle extracts (relative units; kidney: 6 weeks 88 10% vs 100 2%; 11 weeks 76 3% vs 100 4%, P<0·05; vastus lateralis: 6 weeks 95 7% vs 100 10%; 11 weeks 59 4% vs 100 2%, P<0·001); (2) similar at both ages in thoracic aorta (relative units; 6 weeks 121 6% vs 105 5%; 11 weeks: 91 14% vs 100 4%); and (3) increased at both ages in left ventricle extracts (relative units; 6 weeks 114 2% vs 99 9%, P<0·05; 11 weeks 119 7% vs 95 3%, P<0·05).These data support the existence of tissue-specific dependence of IGF-I mRNA on GH levels during adulthood, reflected by the different behavior of IGF-I expression for each tissue in conditions of progressive decrease of GH levels.

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“…Effects of DIO on femoral biomechanics V Brahmabhatt et al lean littermates. 13 The shorter femora in the faafa rats are due to growth hormone de®ciency and low somatomedin-C levels 29 through which GH exerts its effects on bone. It should also be noted that obese children show a blunted GH response to stimuli and have impaired GH secretion during sleep.…”

Section: Discussionmentioning

confidence: 99%

The effects of dietary-induced obesity on the biomechanical properties of femora in male rats

et al. 1998

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OBJECTIVE: To assess the effects of diet-induced obesity (DIO), on the biomechanical and biochemical properties of the femur in mature male rats. DESIGN AND SUBJECTS: Two groups of male rats were studied. The DIO experimental group was fed a high caloric diet and a 31% sucrose solution as drinking¯uid for a month, whereas the control group was fed lab chow and tap water. MEASUREMENT: Body weight; body water; lean body mass; femoral length; average cortical thickness; outer anteroposterior diameter; outer mediolateral diameter; cortex area; moment of inertia; cortical and cancellous bone hydration; tendon and muscle hydration; ash content of cortical and cancellous bone; ultimate load; de¯ection at ultimate load; ultimate strength; stiffness; elastic modulus and energy absorption capacity. RESULTS:`Gainers' (®nal body weight in excess of three standard error of mean of the controls) were 19.1% heavier, with higher body fat, whereas body water, lean body mass, hydration of cancellous bone and ash content of cortical bone were lower, when compared to controls. Rats that failed to gain weight, despite the high caloric diet, were termed`resisters' (weight gain less than three standard error of mean of the controls).Ultimate load, de¯ection at ultimate load and femoral energy absorption capacity were signi®cantly higher in the experimental group when compared to the controls. However, no differences were found among the groups with respect to ultimate stress and stiffness. CONCLUSION: The weight gain produced by DIO may lead to bone adaptation and improved biomechanics.

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Growth Hormone and Prolactin Secretion in Genetically Obese Zucker Rats*

Cited by 54 publications

References 18 publications

Growth Hormone Administration Controls Body Composition Associated with Changes of Thermogenesis in Obese KK-Ay Mice~!2009-08-29~!2010-01-12~!2010-03-26~!

Growth Hormone Administration Controls Body Composition Associated with Changes of Thermogenesis in Obese KK-Ay Mice~!2009-08-29~!2010-01-12~!2010-03-26~!

Tissue-specific response of IGF-I mRNA expression to obesity-associated GH decline in the male Zucker fatty rat

The effects of dietary-induced obesity on the biomechanical properties of femora in male rats

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