A high-protein dietary treatment to intestinally hypotrophic rats induces ghrelin mRNA content and serum peptide level changes

To investigate the effects of amino acids on ghrelin-induced growth hormone (GH), insulin and glucagon secretion in lactating dairy cattle, six Holstein cows were randomly assigned to two infusion treatments in a cross-over design. Mixture solution of amino acids (AMI) or saline (CON) was continuously infused into the left side jugular vein via catheter for 4 h. At 2 h after the start of infusion, synthetic bovine ghrelin was single injected into the right side jugular vein through the catheter. Ghrelin injection immediately increased plasma GH, glucose and non-esterified fatty acids (P<0.05) with no difference between both treatments. Additionally, plasma insulin and glucagon concentrations were increased by ghrelin injection in both treatments. The peak value of plasma insulin concentration was greater in AMI compared with CON (P<0.05). Plasma glucagon concentration showed no difference in the peak value reached at 5 min between both treatments, and then the plasma levels in AMI compared with CON showed sustained higher values (P<0.05). After plasma glucose concentration reached the peak, the decline was greater in AMI compared with CON (P<0.05). These results showed that the increased plasma amino acids may enhance ghrelin action which in turn enhances insulin and glucagon secretions in lactating cows.

show abstract

“…In rats, ghrelin expression and secretion were enhanced by feeding of a high protein diet (Vallejo‐Cremades et al . 2004, 2005).…”

Section: Resultsmentioning

confidence: 99%

Effects of amino acids infused into the vein on ghrelin‐induced GH, insulin and glucagon secretion in lactating cows

Fukumori

Yokotani

Sugino

et al. 2011

Animal Science Journal

View full text Add to dashboard Cite

show abstract

“…1C). In rats, ghrelin expression and secretion were enhanced by feeding of high protein diet (Vallejo‐Cremades et al. 2004, 2005).…”

Section: Resultsmentioning

confidence: 99%

Effects of glucose and amino acids on ghrelin secretion in sheep

Sugino

Kawakita

Fukumori

et al. 2010

Animal Science Journal

View full text Add to dashboard Cite

Two experiments were conducted to elucidate the effects of post-ruminal administration of starch and casein (Exp. 1), plasma amino acids concentrations (Exp. 2), and plasma glucose and insulin concentrations (Exp. 2) on plasma ghrelin concentrations in sheep. In Exp. 1, plasma ghrelin concentrations were determined by four infusion treatments (water, cornstarch, casein and cornstarch plus casein) in four wethers. Abomasal infusion of casein increased plasma alpha-amino N (AAN) concentrations. Infusion of starch or casein alone did not affect plasma ghrelin concentrations, but starch plus casein infusion increased plasma levels of ghrelin, glucose and AAN. In Exp 2, we investigated the effects of saline or amino acids on ghrelin secretion in four wethers. Two hours after the initiation of saline or amino acid infusion into the jugular vein, glucose was also continuously infused to investigate the effects of blood glucose and insulin by hyper-glycemic clump on plasma ghrelin concentrations. Infusion of amino acids alone raised plasma levels of ghrelin, but the higher plasma glucose and insulin concentrations had no effect on plasma ghrelin concentrations. These results suggest that high plasma levels of amino acids can stimulate ghrelin secretion, but glucose and insulin do not affect ghrelin secretion in sheep.

show abstract

“…However, we cannot rule out the possibility that the HP diet stimulates ghrelin secretion from the duodenum. Previous reports indicate that because ghrelin is also produced in the duodenum -the second richest source of ghrelin (Date et al 2000a, Ariyasu et al 2001) -increased serum ghrelin concentrations are associated with the trophic effects on the intestine of an enriched protein diet (Vallejo-Cremades et al 2005). Interestingly, ghrelin was detected in the rumen, reticulum, and omasum, even though it is mainly secreted from the abomasum.…”

Section: Discussionmentioning

confidence: 98%

Increased plasma ghrelin suppresses insulin release in wethers fed with a high-protein diet

Takahashi

Sato

Kato

et al. 2014

Journal of Endocrinology

View full text Add to dashboard Cite

Ghrelin is a multifunctional peptide that promotes an increase of food intake and stimulates GH secretion. Ghrelin secretion is regulated by nutritional status and nutrients. Although a high-protein (HP) diet increases plasma ghrelin secretion in mammals, the mechanisms and the roles of the elevated ghrelin concentrations due to a HP diet have not been fully established. To clarify the roles of elevated acylated ghrelin upon intake of a HP diet, we investigated the regulation of ghrelin concentrations in plasma and tissues in wethers fed with either the HP diet or the control (CNT) diet for 14 days, and examined the action of the elevated plasma ghrelin by using a ghrelin-receptor antagonist. The HP diet gradually increased the plasma acylated-ghrelin concentrations, but the CNT diet did not. Although the GH concentrations did not vary significantly across the groups, an injection of ghrelinreceptor antagonist enhanced insulin levels in circulation in the HP diet group. In the fundus region of the stomach, the ghrelin levels did not differ between the HP and CNT diet groups, whereas ghrelin O-acyltransferase mRNA levels were higher in the group fed with HP diet than those of the CNT diet group were. These results indicate that the HP diet elevated the plasma ghrelin levels by increasing its synthesis; this elevation strongly suppresses the appearance of insulin in the circulation of wethers, but it is not involved in GH secretion. Overall, our findings indicate a role of endogenous ghrelin action in secretion of insulin, which acts as a regulator after the consumption of a HP diet.

show abstract

A high-protein dietary treatment to intestinally hypotrophic rats induces ghrelin mRNA content and serum peptide level changes

Cited by 11 publications

References 36 publications

Effects of amino acids infused into the vein on ghrelin‐induced GH, insulin and glucagon secretion in lactating cows

Effects of amino acids infused into the vein on ghrelin‐induced GH, insulin and glucagon secretion in lactating cows

Effects of glucose and amino acids on ghrelin secretion in sheep

Increased plasma ghrelin suppresses insulin release in wethers fed with a high-protein diet

Contact Info

Product

Resources

About