scholarly journals Large body size in the dog is associated with transient GH excess at a young age

2001 ◽  
Vol 170 (2) ◽  
pp. 479-484 ◽  
Author(s):  
RP Favier ◽  
JA Mol ◽  
HS Kooistra ◽  
A Rijnberk

The main determinants of body size are GH and IGFs. The aim of this study was to investigate whether differences in adult body size of medium-sized and giant dog breeds can be explained by differences in GH release and/or in plasma IGF-I and IGF-II concentrations at a young age. The basal plasma concentrations of GH, IGF-I and IGF-II were determined once weekly in six Great Danes and six beagles from the age of 6 weeks until the age of 24 weeks. In addition, the 6 h secretory profile of GH was determined every 2 weeks. Basal plasma GH concentrations as well as the total area under the curve (AUC) and the AUC above the baseline for GH were significantly higher in Great Danes than in beagles of the same age. In contrast, plasma IGF-I and IGF-II concentrations did not differ significantly between the two breeds. Compared with values in adults, the basal plasma GH concentrations were high until the age of 7 weeks in the beagles, whereas in the Great Danes the basal plasma GH levels remained high during the entire observation period, albeit with a gradual decline. The mean frequency and the mean amplitude of GH pulses tended to be higher in Great Danes than in beagles, although a significant difference was only reached at the age of 19 and 23 weeks for the frequency and at the ages of 9, 11 and 13 weeks for the amplitude. An age-dependent decrease in pulse frequency occurred in the Great Danes. The results of this study demonstrate that differences in adult body size of medium-sized and giant dog breeds are preceded by differences in GH release and not by differences in circulating IGF-I or IGF-II concentrations. Both young Great Danes and young beagles experience a period of high GH release, but this period persists much longer in Great Danes. It is discussed that this difference may be due to delayed maturation of the inhibitory influences of somatostatin on pituitary GH release in the latter dogs.

2017 ◽  
Author(s):  
Wolf U. Blanckenhorn

AbstractA Preprint reviewed and recommended by Peer Community Evolutionary Biology: http://dx.doi.org/10.24072/pci.evolbiol.100027Evidence for selective disadvantages of large body size remains scarce in general. Previous phenomenological studies of the yellow dung fly Scathophaga stercoraria have demonstrated strong positive sexual and fecundity selection on male and female size. Nevertheless, the body size of flies from a Swiss study population has declined by almost 10% from 1993 to 2009. Given substantial heritability of body size, this negative evolutionary response of an evidently positively selected trait suggests important selective factors being missed (e.g. size-selective predation or parasitism). A periodic epidemic outbreak of the fungus Entomophthora scatophagae allowedassessment of selection exerted by this parasite fatal to adult flies. Fungal infection varied over the season from ca. 50% in the cooler and more humid spring and autumn to almost 0% in summer. The probability of dying from fungal infection increased with adult body size. All infected females died before laying eggs, so there was no fungus impact on female fecundity beyond its impact on mortality. Large males showed the typical mating advantage in the field, but this pattern of positive sexual selection was nullified by fungal infection. Mean fluctuating asymmetry of paired appendages (legs, wings) did not affect the viability, fecundity or mating success of yellow dung flies in the field. This study demonstrates rare parasite-mediated disadvantages of large adult body size in the field. Reduced ability to combat parasites such as Entomophthora may be an immunity cost of large size in dung flies, although the hypothesized trade-off between fluctuating asymmetry, a presumed indicator of developmental instability and environmental stress, and immunocompetence was not found here.


Genetics ◽  
1989 ◽  
Vol 122 (1) ◽  
pp. 193-203 ◽  
Author(s):  
D E Cowley ◽  
D Pomp ◽  
W R Atchley ◽  
E J Eisen ◽  
D Hawkins-Brown

Abstract Embryo transfers were used to demonstrate that the genotype of the mother providing the uterine developmental environment significantly influences postnatal growth and adult body size of her progeny. Irrespective of their own genotype, mouse embryos transferred into the uterus of an inbred strain with large body size (C3H) had greater body weights, longer tails and higher growth rates than those transferred into the uterus of a strain with small body size (SWR). Uterine heterosis on body size was smaller than progeny heterosis, and both progeny and uterine heterosis persisted in adult mice. Uterine litter size was significantly negatively associated with body weight, tail length, growth rate and the timing of developmental events. The inbred SWR strain was more sensitive to the embryo transfer procedure than the C3H strain, but effects due to embryo transfer were moderate. Prenatal uterine effects have ramifications for biotechnologies utilizing embryo transfer as well as predictions about evolutionary change by selection.


1998 ◽  
pp. 302-306 ◽  
Author(s):  
M Sohmiya ◽  
K Ishikawa ◽  
Y Kato

We have investigated the effect of human GH on erythropoietin (EPO) secretion in eight anemic patients with chronic renal failure (CRF) (three males and five females, aged from 46 to 83 years). Recombinant human GH was infused subcutaneously at a flow rate of 2 microg/kg body weight per 0.1 ml/h for 72 h using a portable infusion pump. Blood samples were obtained immediately before and 2, 4, 6, 12, 24, 36, 48, 60, 72, 84, 96, 108, 120 and 168 h after the start of GH infusion. Storage urine samples were obtained before and 24, 48 and 72 h after the start of the infusion. The mean (+/- S.E.M.) basal plasma GH levels increased from 1.9 +/- 0.3 to 18.8 +/- 0.7 microg/l during the GH infusion. Plasma IGF-I levels increased 12 h after the start of GH treatment and the mean peak values of 403.6 +/- 38.5 microg/l were obtained at 72 h. Plasma EPO levels increased 6 h after the start of GH infusion, and the peak values of 38.4 +/- 11.6 IU/l were obtained at 96 h (P < 0.05 vs basal values 24.5 +/- 7.2 IU/l). Reticulocyte counts increased from 28.7 +/- 5.2 x 10(3)/microl to 40.3 +/- 8.0 x 10(3)/l at 108 h, 43.6 +/- 9.2 x 10(3)/microl at 120 h and 41.7 +/- 7.7 x 10(3)/microl at 160 h (P < 0.05). Serum urea nitrogen decreased at 72 h (P < 0.05), whereas there was no significant change in urinary excretion of nitrogen. Hemoglobin levels were not significantly changed throughout the experimental period. These findings indicate that human GH has a stimulating effect on EPO secretion in anemic patients with CRF.


1990 ◽  
Vol 122 (6) ◽  
pp. 745-752 ◽  
Author(s):  
Patrick Pagesy ◽  
Jacques Y. Li ◽  
Françoise Rentier-Delrue ◽  
Olivier Delalande ◽  
Yves Le Bouc ◽  
...  

Abstract. Some patients with active acromegaly have elevated plasma IGF-I concentrations with only minimal elevation of plasma GH. We compared adenomatous GH and SRIH expression in 3 such patients (patients No. 1, 2 and 3; basal plasma GH level < 4 μg/l) and in 3 acromegalic patients with high basal plasma GH level (patients No. 4, 5 and 6; 51.7 ± 16.1 μg/l, mean ± sem). By immunocytochemistry, all the tumours proved to be somatotropic adenomas. At the ultrastructural level, signs of low secretory activity were observed in adenomas from patients No. 2 and 3. Perifused adenoma cells of patients No. 1, 2 and 3 released very little GH compared with those of patients No. 4, 5 and 6 (1± 0.37 vs 51.5± 34.1 μg · (10−6 cells) · min−1, p< 0.001). Adenoma SRIH content was 65.7 and 30.6 pg/mg proteins in patients No. 1 and 2, whereas it was undetectable in the others (patients No. 4, 5 and 6). Northern blot analysis showed that the GH gene was poorly expressed in the adenomas from patients No. 1, 2 and 3 compared with the adenomas from patients No. 4, 5 and 6. SRIH mRNA was detected in all 6 adenomas. However, the signal was more intense in the adenomas from patients No. 1, 2 and 3 than in those from patients No. 4, 5 and 6. In conclusion, because of the variability of the biosynthetic and secretory potential of the somatotropic adenomas, patients harbouring this type of pituitary tumours can exhibit a wide range of plasma GH levels. In acromegaly with minimal elevation of plasma GH, the synthesis of SRIH by the adenoma cells themselves could play a role in the inhibition of GH expression.


Zootaxa ◽  
2010 ◽  
Vol 2411 (1) ◽  
pp. 33 ◽  
Author(s):  
KAMBIZ MINAEI ◽  
LAURENCE MOUND

Species of the genus Chirothrips Haliday breed and pupate only within grass florets. Each larva is restricted to a single floret, and adult body size is thus presumably related to floret size. Despite this, some Chirothrips species are distinguished only on states that are related to body size. The validity of some commonly recorded members of the C. manicatus species-group, including C. africanus and C. pallidicornis, is therefore considered questionable. Character states that have been used to define the genus Agrostothrips Hood are shown to be variable, and this genus is placed as a new synonym of Chirothrips. An identification key, based on illustrated structural differences, is provided to the Chirothrips known from Iran: C. aculeatus, C. atricorpus, C. kurdistanus, C. manicatus, C. meridionalis and C. molestus.


1970 ◽  
Vol 33 (3) ◽  
pp. 325-336 ◽  
Author(s):  
A. Roberto Frisancho ◽  
Stanley M. Garn ◽  
Werner Ascoli
Keyword(s):  

Oecologia ◽  
1995 ◽  
Vol 102 (4) ◽  
pp. 433-442 ◽  
Author(s):  
H�kan Sand ◽  
G�ran Cederlund ◽  
Kjell Danell

1991 ◽  
Vol 124 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Hiroshi Bando ◽  
Chenyu Zhang ◽  
Yukinobu Takada ◽  
Ryuichi Yamasaki ◽  
Shiro Saito

Abstract. The GHRH test and L-dopa test were performed in 12 normal young men (24.1 ± 1.1 years) and 12 normal elderly men (77.8±1.4 years) to investigate age-related changes in secretion of GHRH, GH and IGF-I. The basal plasma levels of GHRH and GH were not significantly different in young and elderly men, but the basal plasma level of IGF-I was higher in the young men (159.0± 11.7 vs 86.7± 11.6 μg/1). The area under the curve for plasma GH in the GHRH test was less in the elderly group (35.1 ±5.9 vs 11.2 ± 2.1 μg · h−1 · 1−1, p<0.001). The AUCs for the plasma GHRH and GH responses in the L-dopa test in young and elderly men were 32.0±2.7 vs 20.3±1.8 ng · h−1 · 1−1 (p<0.001), and 21.8±4.6 vs 5.4±1.1 μg · h−1 · 1 (p<0.01), respectively, indicating decreased releases of GHRH and GH in the elderly. Correlations between the AUCs for plasma GHRH and GH responses in L-dopa were found in both groups, but the ratio of the AUCs for GH/GHRH was lower in the elderly group. The elderly group showed a significant correlation between the basal plasma IGF-I level and the AUCs for plasma GH in the GHRH and L-dopa tests. These results suggest that elderly men have a decreased reserve of hypothalamic GHRH, resulting in secondarily impaired GH release, which may lead to a lower level of IGF-I than in young men.


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