GH secretory responses to ghrelin and GHRH in growing and lactating dairy cattle

Itoh, Fumiaki; Komatsu, Tokushi; Yonai, Miharu; Sugino, Toshihisa; Kojima, Masayasu; Kangawa, Kenji; Hasegawa, Yoshihisa; Terashima, Yoshiaki; Hodate, Koichi

doi:10.1016/j.domaniend.2004.06.001

Cited by 53 publications

(49 citation statements)

References 23 publications

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“…However, our cows investigated 6 weeks ap developed only a twofold increase while cows in early lactation responded with a fourfold increase in plasma acyl ghrelin after 9-h feed deprivation. The greater increase in acyl ghrelin in H cows pp compared with ap is in line with earlier findings (Itoh et al 2005, Bradford & Allen 2008, stating that negative EB increases periprandial acyl ghrelin concentrations (Bradford & Allen 2008). During ad libitum feeding, only H cows (not L cows) had a significantly higher acyl ghrelin concentration pp when compared with the ap period.…”

Section: Figuresupporting

confidence: 80%

“…Wertz-Lutz et al (2006) found a weak increase in feed intake upon acyl ghrelin injection; however, neither s.c. (Roche et al 2008) nor centrally infused acyl ghrelin (Iqbal et al 2006) leads to a significant increase in feed intake, so an orexigenic role of acyl ghrelin in ruminant species appears questionable. Acyl ghrelin is elevated during early lactation (Itoh et al 2005, Bradford & Allen 2008, a period characterized by high body fat mobilization. This suggests that, in addition to its role in preventing starvation, ghrelin exerts a prominent role in the regulation of fat metabolism.…”

Section: Introductionmentioning

confidence: 99%

“…A small proportion of ghrelin is acylated (mostly octanoylated) by ghrelin O-acyltransferase (GOAT) at Ser 3 (Yang et al 2008), resulting in the secretion of both acyl and non-acyl ghrelin into the blood stream (Hosoda et al 2000, ThidarMyint et al 2006. Both forms are involved in the maintenance of energy homeostasis (ThidarMyint et al 2006), but only the acyl form of ghrelin exhibits endocrine activity by activating GH secretagogue receptor (GHSR) signalling and GH release (Itoh et al 2005, Iqbal et al 2006, Bradford & Allen 2008. In ruminants, plasma concentrations of acyl ghrelin increase before meals, in response to fasting, and with decreasing rumen fill (Sugino et al 2002a, Wertz-Lutz et al 2006, Gregorini et al 2009), whereas feeding suppresses the ghrelin surge (Wertz-Lutz et al 2006).…”

Section: Introductionmentioning

confidence: 99%

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Plasma ghrelin is positively associated with body fat, liver fat and milk fat content but not with feed intake of dairy cows after parturition

Börner¹,

Derno²,

Hacke³

et al. 2012

Journal of Endocrinology

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Ghrelin is a gastrointestinal peptide hormone that is present in blood mostly in a non-posttranslationally modified form, with a minor proportion acylated at Ser 3 . Both ghrelin forms were initially assigned a role in the control of food intake but there is accumulating evidence for their involvement in fat allocation and utilization. We investigated changes in the ghrelin system in dairy cows, exhibiting differences in body fat mobilization and fatty liver, from late pregnancy to early lactation. Sixteen dairy cows underwent liver biopsy and were retrospectively grouped based on high (H) or low (L) liver fat content post-partum. Both groups had a comparable feed intake in week K6 (before parturition) and week 2 (after parturition). Only before parturition was preprandial total ghrelin concentration higher in L than in H cows and only after parturition was the basal plasma concentration of non-esterified fatty acids higher in H than in L cows. Both before and after parturition, H cows had higher preprandial plasma concentrations of acyl ghrelin, a higher acyl:total ghrelin ratio, lower plasma triacylglyceride concentrations and a lower respiratory quotient compared with L cows. These group differences could not be attributed to an allelic variant of the acyl ghrelin receptor. Rather, the ratio of acyl:total ghrelin correlated with several aspects of fat metabolism and with respiratory quotient but not with feed intake. These results show that endogenous ghrelin forms are associated with fat allocation, fatty liver, and utilization of fat during the periparturient period.

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Section: Figuresupporting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Plasma ghrelin is positively associated with body fat, liver fat and milk fat content but not with feed intake of dairy cows after parturition

Börner¹,

Derno²,

Hacke³

et al. 2012

Journal of Endocrinology

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show abstract

“…Energy demand during lactation is very high and is met primarily by increased feed intake, although there is some mobilization of reserves, especially of lipids from adipose tissues. Itoh et al (2005) in dairy cattle showed that plasma ghrelin concentrations are significantly higher in early lactating cows than in pregnant heifers or non-lactating cows. In addition, peak values of ghrelin-induced GH secretion have been demonstrated to be signifi cantly higher in early lactating than in non-lactating cows (Itoh et al, 2005).…”

Section: Ghrelin In Pregnancy and Lactationmentioning

confidence: 99%

“…Besides pathological conditions mentioned earlier, many physiologic factors including age and gestational age for newborns, gender, pregnancy, lactation, body mass, body composition and fi tness, may determine plasma concentration of ghrelin as well (Kozakowski et al, 2004;Itoh et al, 2005). An important contributor is also a response to extrinsic factors like: feed intake and caloric restriction, the type of feed, sleep duration and stress (Yokoyama et al, 2005;Yang et al, 2007).…”

Section: Ghrelin Expression Plasma Ghrelin Level and Potential Implimentioning

confidence: 99%

Ghrelin - characterization, regulation of synthesis, release and possible role in reproduction

Litwiniec¹,

Izdebska²,

Włodarczyk³

et al. 2008

J. Anim. Feed Sci.

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Ghrelin is a peptide, composed of 28-amino acid residues, with a characteristic modifi cation by n-octanoid acid, covalently linked to the serine-3. Considering a genomic position, the gene of ghrelin in humans is located on chromosome 3p25-26. Major source of ghrelin seems to be the stomach, but other tissues and organs such as: the small intestine, pancreas, pituitary gland, arcuate nucleus of the hypothalamus, kidney, placenta, lungs, testis, ovaries and adrenal glands, were reported to synthesize this peptide also. Body weight was proved to be superior to food intake for ghrelin regulation and an impaired hormone response to feeding status appeared in obese individuals. Based on experimental data, which show that ghrelin and its receptor are expressed in normal human ovary and testis, it has been proposed that ghrelin acting as either an endocrine and/or a paracrine signal, may play a major role in the endocrine network that integrates energy balance and reproduction.

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Effects of Environment on Metabolism

Baumgard¹,

Rhoads²

2012

Environmental Physiology of Livestock

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GH secretory responses to ghrelin and GHRH in growing and lactating dairy cattle

Cited by 53 publications

References 23 publications

Plasma ghrelin is positively associated with body fat, liver fat and milk fat content but not with feed intake of dairy cows after parturition

Plasma ghrelin is positively associated with body fat, liver fat and milk fat content but not with feed intake of dairy cows after parturition

Ghrelin - characterization, regulation of synthesis, release and possible role in reproduction

Effects of Environment on Metabolism

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