Effects of long-term administration of pituitary-derived bovine growth hormone and estradiol on growth in steers.

Enright, W. J.; Quirke, J. F.; Gluckman, Peter D.; Breier, Bernhard H.; Kennedy, Laurence; Hart, L C; Roche, J. F.; Coert, A.; Allen, Paul

doi:10.2527/1990.6882345x

Cited by 75 publications

(40 citation statements)

References 22 publications

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“…Boars have also been found to have greater circulating concentrations of IGF-I than gilts or barrows (Dunshea et al 1993, Owens et al 1999, Clapper et al 2000. Administration of E2 implants has been reported to increase circulating concentrations of IGF-I in barrows (Rempel & Clapper 2002), steers (Enright et al 1990, Hays et al 1995, and ovariectomized ewes (Clapper et al 1998). Thus, E2 may mediate its growth-promoting effects through increases in circulating concentrations of IGF-I.…”

Section: Introductionmentioning

confidence: 97%

Effects of decreased estradiol-17β on the serum and anterior pituitary IGF-I system in pigs

Hilleson-Gayne

Clapper

2005

Journal of Endocrinology

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To further delineate the role of estradiol in the IGF system an experiment was conducted to determine the dosage of the aromatase inhibitor, anastrozole, needed to decreases serum concentrations of estradiol-17 (E2) in maturing boars. A second experiment was conducted to determine if administration of anastrozole to growing boars decreased serum concentrations of E2 and affected components of the serum and anterior pituitary gland (AP) IGF system vs untreated boars and barrows. In Experiment 1, 12 crossbred boars (292 days, 158 kg) were administered either 0, 1 or 10 mg/day anastrozole (n=4/group) beginning on day 1. Blood samples were collected every 7-14 days. Mean serum concentrations of E2 were decreased (P<0·05) in the 10 mg group vs the 0 and 1 mg groups by day 36; however, no difference (P>0·05) existed between the 0 and 1 mg groups. In Experiment 2, 24 crossbred boars and 12 barrows (101 days, 44 kg) were stratified by litter to one of three treatment groups (n=12): boars administered 10 mg/day anastrozole, boars administered 0 mg/day, and barrows administered 0 mg/day. Blood samples were collected and pigs were weighed on day 0 and every 14 days thereafter, then killed on day 84 when blood and APs were collected. The 10 mg/day pigs were fed the anastrozole-amended diet beginning on day 1. Mean serum concentrations of E2 did not differ (P>0·05) between the 10 mg/day pigs and 0 mg/day pigs on day 0; however, on day 15 through to 84 mean serum concentrations of E2 were greater (P<0·05) in 0 mg/day pigs than in the 10 mg/day pigs. Mean percentage increase in serum concentrations of IGF-I was greater (P<0·05) in untreated boars than anastrozole-treated boars and barrows from day 58 through to 84. Mean percentage of basal IGF-I increased (P<0·05) from day 29 through to 84 in untreated boars. Mean relative amounts of AP IGFbinding protein (IGFBP)-2 and -5 were less (P<0·01) in 10 mg/day pigs than in the 0 mg/day pigs, but each was greater (P<0·01) than in barrows administered 0 mg/day. These results indicate anastrozole administered at a dosage of 10 mg/day suppresses serum concentrations of E2 in pigs. Administration of anastrozole to boars reduced the percentage increase in serum concentrations of IGF-I and relative amounts of AP IGFBP-2 and -5. These data further support a role for E2 in regulating components of the IGF system in pigs.

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Section: Introductionmentioning

confidence: 97%

Effects of decreased estradiol-17β on the serum and anterior pituitary IGF-I system in pigs

Hilleson-Gayne

Clapper

2005

Journal of Endocrinology

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“…In addition, gonadal steroid implants improve growth rates, enhance accretion of lean tissue and improve the conversion efficiency of feed in healthy steers (Unruh 1986, Breier et al 1988, Enright et al 1990) and this may be beneficial during catabolic disease. During infection, gonadal steroids are immunomodulatory, but their role in host defense is not well understood; actions range from increased severity of infection to enhanced recovery from infection (Grossman 1984(Grossman , 1985(Grossman , 1994.…”

Section: Introductionmentioning

confidence: 99%

Estradiol/progesterone implants increase food intake, reduce hyperglycemia and increase insulin resistance in endotoxic steers

McMahon

Elsasser²,

Gunter³

et al. 1998

Journal of Endocrinology

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High doses of lipopolysaccharide (LPS) induce transient hyperglycemia, then chronic hypoglycemia and increased insulin resistance. In addition, appetite is reduced, while body temperature and concentrations of cortisol and tumor necrosis factor alpha (TNF ) are elevated. Furthermore, concentrations of GH and IGF-I are reduced in cattle. The objectives of this study were to determine whether a gonadal steroid implant (20 mg estrogen and 200 mg progesterone) given to endotoxemic steers would: (1) reduce hyperglycemia, reduce hypoglycemia, reduce insulin resistance, (2) reduce changes in concentrations of GH and IGF-I, (3) reduce inappetence and reduce concentrations of blood urea nitrogen (BUN) and nonesterified fatty acids (NEFA), and (4) reduce fever and concentrations of TNF and cortisol. Holstein steers were assigned within a 2 2 factorial arrangement of treatments as follows (n=5 per group): C/C, no steroid and vehicle; S/C, steroid and vehicle; C/E, no steroid and LPS (1 µg/kg body weight (BW), i.v.); S/E, steroid and endotoxin. Steroid implants were given at 20 weeks of age (day 0) and serial blood samples (15 min) were collected on day 14 for 8 h, with vehicle or LPS injected after 2 h. Intravenous glucose tolerance tests (100 mg/kg BW) were carried out at 6 h and 24 h. Hyperglycemia was 67% lower (P<0·05) in S/E-compared with C/E-treated steers between 30 and 150 min after i.v. injection of LPS.Hypoglycemia developed after 4 h and insulin resistance was greater in S/E-compared with C/E-treated steers (P<0·05) at 6 and 24 h. Concentrations of IGF-I were restored earlier in steroid-treated steers than in controls. Concentrations of GH were not affected by steroids, but increased 1 h after injection of LPS, then were reduced for 2 h. Appetite was greater (P<0·05) in S/E-(2·1% BW) compared with C/E-treated steers (1·1% BW) (pooled ...=0·3). Concentrations of NEFA increased after injecting LPS, but concentrations were lower (P<0·05) in S/E-compared with C/E-treated steers. LPS did not affect concentrations of BUN, but concentrations were lower in steroid-treated steers. Steroids did not affect body temperature or concentrations of TNF and cortisol. In summary, gonadal steroids reduce hyperglycemia, reduce inappetence and tissue wasting, but increase insulin resistance. Furthermore, concentrations of IGF-I are restored earlier in steroid-treated than in non-steroid-treated steers injected with LPS. It is concluded that gonadal steroids reduce severity of some endocrine and metabolic parameters associated with endotoxemia. However, it is unlikely that gonadal steroids acted via anti-inflammatory and immunosuppressive actions of glucocorticoids or through reducing concentrations of cytokines.

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“…혈중 glucose, 중성지방 및 총단백질 농도 역시 단백질사료의 N fraction과의 직접적인 연관성은 찾기 어려운 것으로 나타나 본 연구팀의 최근 연구결과와 유사하였다. (Enright et al, 1990), 반추위로 흡수되는 암모니아가 증가하면 간에서 요소합성량을 증가시켜 BUN 수치를 높이는 것으로 알려져 있다 (Choi, 2015). 본 연구의 평균 반추위 암모니아-N 결과를 보면 AB1 구가 유의적으로 높고, B2구와 B3C구가 유사하며, 대조구가 수치적으로 낮게 나타나는 등 다소 상반된 결과가 나타 났다 (Table 3).…”

Section: Resultsunclassified

Changes in ruminal fermentation and blood metabolism in steers fed low protein TMR with protein fraction-enriched feeds

Choi¹

2016

Korean Journal of Agricultural Science

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Four ruminally cannulated Holstein steers (BW 482.9 ± 8.10 kg), fed low protein TMR (CP 11.7%) as a basal diet, were used to investigate changes in rumen fermentation and blood metabolism according to protein fraction, cornell net carbohydrates and protein system (CNCPS), and enriched feeds. The steers, arranged in a 4 × 4 Latin square design, consumed TMR only (control), TMR supplemented with rapeseed meal (AB1), soybean meal (B2), and perilla meal (B3C), respectively. The protein feeds were substituted for 23.0% of CP in TMR. Ruminal pH, ammonia-N, and volatile fatty acids (VFA) in rumen digesta, sampled through ruminal cannula at 1 h-interval after the morning feeding, were analyzed. For plasma metabolites analysis, blood was sampled via the jugular vein after the rumen digesta sampling. Different N fraction-enriched protein feeds did not affect (p > 0.05) mean ruminal pH except AB1 being numerically lower 1 -3 h post-feeding than the other groups. Mean ammonia-N was statistically (p < 0.05) higher for AB1 than for the other groups, but VFA did not differ among the groups. Blood urea nitrogen was statistically (p < 0.05) higher for B2 than for the other groups, which was rather unclear due to relatively low ruminal ammonia-N. This indicates that additional studies on relationships between dietary N fractions and ruminant metabolism according to different levels of CP in a basal diet should be required.

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Effects of long-term administration of pituitary-derived bovine growth hormone and estradiol on growth in steers.

Cited by 75 publications

References 22 publications

Effects of decreased estradiol-17β on the serum and anterior pituitary IGF-I system in pigs

Effects of decreased estradiol-17β on the serum and anterior pituitary IGF-I system in pigs

Estradiol/progesterone implants increase food intake, reduce hyperglycemia and increase insulin resistance in endotoxic steers

Changes in ruminal fermentation and blood metabolism in steers fed low protein TMR with protein fraction-enriched feeds

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