Dietary fatty acids modulate hormone repsonses in lactating cows: Mechanistic role for 5′-deiodinase activity in tissue

Romo, G.A.; Elsasser, T. H.; Kahl, Stanislaw; Erdman, R.A.; Casper, D. P.

doi:10.1016/s0739-7240(97)00046-5

Cited by 21 publications

(21 citation statements)

References 29 publications

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“…Similar results have been obtained by other authors (Kapp et al 1979;Gerloff et al 1986;Nikolić et al 1997;Stang et al 1998b;Reist et al 2002). Romo et al (1997) reported that in consequence of liver steatosis, FFA accumulate in the liver parenchyma, and it has been demonstrated that some fatty acids inhibit type-I liver 5'-deiodinase activity.…”

Section: Resultssupporting

confidence: 88%

Blood Concentrations of Thyroid Hormones and Lipids and Content of Lipids in the Liver of Dairy Cows in Transitional Period

Đoković

Šamanc²,

Jovanović

et al. 2007

Acta Vet. Brno

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The aim of the present investigation was to determine the correlation in the blood concentrations of thyroid hormones, lipids and glucose as well as the content of lipids in the liver of dairy cows in the transitional period.The animals (n = 40) were divided into four groups: the first group included late pregnant cows (n = 10) from the 10 th to 4 th day before calving; the second group included late pregnant cows (n = 10) from the 4 th to 1 st day before calving; the third group included clinically puerperal healthy cows (n = 10), whereas the fourth group included puerperal cows with clinical symptoms of ketosis (n = 10). Samples of liver and blood tissues were taken from all cows. Pathohistological examination of liver samples showed statistically significantly higher (p < 0.01) lipid infiltration in ketotic cows compared to healthy cows in late pregnancy and puerperium. Biochemical examination of blood serum showed significantly higher values (p < 0.01) of free fatty acids in ketotic cows, such as significantly lower blood concentrations of glucose (p < 0.01), triacylglycerols (p < 0.01), total cholesterol (p < 0.05), triiodthyronine (p < 0.05) and thyroxine (p < 0.05), compared to the values obtained in the blood serum in the groups of healthy cows before and after calving. In this study, significantly positive correlations were determined between the content of lipids in the liver and blood concentration of free fatty acids (r = 0.51; p < 0.05) as well as the negative ones between the content of lipids in the liver and blood concentrations of glucose (r = -0.69; p < 0.05), triacylglycerols (r = -0.55; p < 0.05) and total cholesterol (r = -0.50; p < 0.05) in the group of ketotic cows. Our investigations suggested that a hypothyroidal status was established in ketotic cows and that the blood concentrations of free fatty acids, triacylglycerols, total cholesterol and glucose served as major biochemical indicators in determining liver steatosis in the dairy cows in the transitional period.

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Section: Resultssupporting

confidence: 88%

Blood Concentrations of Thyroid Hormones and Lipids and Content of Lipids in the Liver of Dairy Cows in Transitional Period

Đoković

Šamanc²,

Jovanović

et al. 2007

Acta Vet. Brno

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“…5 This is probably due to the higher dose of TRH administered in both the present and the more recent study. 20 The TRH challenge induced a large range of bTSH values. These values stayed within the limits of this study's RIA and involved the whole range of those presented for reference interval (extremes included).…”

Section: Discussionmentioning

confidence: 99%

“…The bTSH value that corresponds to the mean count of the zero minus 2 SD transposed onto the standard curve was defined as the MDL in this RIA. The accuracy test was carried out by adding known concentrations (5,10,15,20, and 25 mU) of bTSH to 1 ml of bovine plasma. The test was performed in duplicate in the plasma from 2 cows.…”

Section: Characteristics Of the Ria Btshmentioning

confidence: 99%

Development and Validation of a Radioimmunoassay for Thyrotropin in Cattle

et al. 2007

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Abstract. In mammals, thyrotropin, or thyroid-stimulating hormone (TSH), assay is used for the diagnosis of primary hypothyroidism. Hypothyroidism is the most common type of thyroid disorder in cattle. The aim of this study was to develop and validate, under physiologic and pathologic conditions, a radioimmunoassay (RIA) for bovine TSH (bTSH). Double RIA was performed with purified bTSH and specific bovine antiserum. Laboratory validation included research of minimal detection limit, accuracy, and reproducibility. The physiologic validation included a thyrotropin-releasing hormone (TRH) challenge performed on euthyroid cows and a follow-up of bTSH concentration over a 24-hour period. Furthermore, bTSH concentration was assayed in a large population of healthy dairy and beef cows to define reference interval. The pathologic validation was made by assaying bTSH and thyroid hormones on healthy and goitrous newborn calves. The minimum detection limit (MDL) for bTSH assay was 1.3 mU/ml. The recovery was 101% to 106%. The intra-and interassay coefficients of variation (CVs) ranged from 5% to 11% and 11% to 15%, respectively. The RIA covered the whole range of physiologic bTSH values, as shown by bTSH values induced by TRH-challenge. A pulsatile secretion of bTSH was observed, accompanied by a diurnal variation with lower night values than day values. Reference intervals of bTSH ranged from 1.3 to 13.0 mU/ml for beef and dairy breeds. Finally, bTSH easily discriminated goitrous newborn calves from healthy ones, leading to the definition of a cutoff value of 35 mU/ml. The bTSH assay positively reacted to physiologic and pathologic conditions. The accuracy and precision of the RIA were satisfying.

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“…In cattle the plasma levels of thyroid hormones may be altered also by other nutrition-and metabolism-related factors, such as selenium and/ or iodine deficiency/supplementation (Wichtel et al, 1996;Awadeh et al, 1998), growth hormone releasing factor and somatotropin administration (Kahl et al, 1995), providing fat-or starchenriched diet (Bunting et al, 1996;Romo et al, 1997;Blum et al, 2000), and feed contaminants, for instance goitrogen chemicals (Gennano-Soffietti et al, 1988;Bernal et al, 1999;rift et al, 1999a, b) and certain ergot like alkaloids produced by endophyte fungi (Neotyphodium coenophialum) of tall fescue (Festuca arundinacea; known as a really existing form on feed contamination only in North America) (Hurley et al, 1981;Browning et al, 1998Browning et al, , 2000.…”

Section: Basic Physiology Nutritional Factors Influencing Thyroid Fumentioning

confidence: 99%

Clinical endocrinology of thyroid gland function in ruminants

Huszenicza¹,

Kulcsár²,

Rudas³

2002

Vet. Med.

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After briefly introducing the basec steps in production and metabolism of thyroid hormones, the author gives an overview of nutritional, metabolic and disease related factors and endocrine interactions influencing thyroid gland function in ruminants, particularly in the postpartum dairy cow. Involvement of thyroid hormonal regulation of seasonal patterns of reproduction as well as ovarian endocrine function are discussed.Keywords: thyroxin; triiodothyronine; ovary; metabolism; ruminants Abbreviations: 5'D = 5'-deiodinase (syn.: outer-ring deiodinase); 5D = 5-deiodinase (syn.: inner-ring deiodinase); BHB = βOH-butyrate; E 2 = 17β-estradiol; FSH = follicle stimulating hormone; GH = growth hormone; GnRH = gonadotropin releasing hormone; hCG = human chorionic gonadotropin; IGF-I = insulin-like growth factor-I (syn.: somatomedin C); IL = interleukin; LH = luteinizing hormone; mRNA = messenger ribonucleic acid; NEB = negative energy balance; NEFA = non-esterified fatty acids; P 4 = progesterone; PVN = paraventricular nucleus of the hypothalamus; rT 3 = 3,3',5'-triiodothyronine (syn.: reverse-triiodothyronine); T 3 = 3,3',5-triiodothyronine; T 4 = thyroxine; TNFα = tumor necrosis factor-α; TRH = thyrotropin-releasing hormone; TSH = thyroid-stimulating hormone (syn.: thyrotropin)

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Dietary fatty acids modulate hormone repsonses in lactating cows: Mechanistic role for 5′-deiodinase activity in tissue

Cited by 21 publications

References 29 publications

Blood Concentrations of Thyroid Hormones and Lipids and Content of Lipids in the Liver of Dairy Cows in Transitional Period

Blood Concentrations of Thyroid Hormones and Lipids and Content of Lipids in the Liver of Dairy Cows in Transitional Period

Development and Validation of a Radioimmunoassay for Thyrotropin in Cattle

Clinical endocrinology of thyroid gland function in ruminants

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