Oxyntomodulin analog and exendin-4 derivative lower plasma glucose in cattle.

The present study was undertaken with the aim of examining whether and how exendin-4 (1-3) fragment, ie, Ex-4 (1-3) fragment, contributes to the regulation of glucose. An analog of oxyntomodulin (OXM) ([Gly, Glu]-OXM), a glucagon analog ([Gly, Glu]-glucagon), and two derivatives of Ex-4 (glucandin and [Gly, Glu]-glucandin) were synthesized by substituting with Gly, Glu at the N-terminuses of OXM and glucagon and/or by attaching Ex-4 (30-39) amide at the C-terminus of glucagon. Effects of these peptides on plasma insulin and glucose concentrations were investigated in cattle by conducting 3 in vivo experiments.

Insulinotropic action of bombesin-like peptides mediated by gastrin-releasing peptide receptors in steers.

The present study characterizes the receptor that mediates the insulinotropic action of bombesin-like peptides (BLP) in ruminants. Eight Holstein steers were randomly and intravenously injected with synthetic bovine gastrin-releasing peptide (GRP; 0.9 nmol/kg BW), neuromedin B (NMB; 0.

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 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.

Oxyntomodulin attenuates exendin-4-induced hypoglycemia in cattle.

Oxyntomodulin (OXM), glucagon, glucagon-like peptide-1 (GLP-1), and exendin-4 (Ex-4) are peptide hormones that regulate glucose homeostasis in monogastric and ruminant animals. Recently, we reported that the insulin-releasing effects of OXM and glucagon in cattle are mediated through both GLP-1 and glucagon receptors. The purpose of this study was to examine the mechanisms of the glucoregulatory actions induced by Ex-4, GLP-1, OXM, and glucagon and the interrelationships among these hormones in cattle.

Bombesin-like peptides stimulate growth hormone secretion mediated by the gastrin-releasing peptide receptor in cattle.

This study was designed to determine the effects of bombesin-like peptides (BLPs) on the secretion of growth hormone (GH) and to characterize the receptor subtypes mediating these effects in cattle. Four experiments were conducted: (1) six steers were randomly assigned to receive intravenous (IV) bolus injections of 0, 0.2, 1.

Sulfated cholecystokinin-8 increases ghrelin secretion but does not affect oxyntomodulin in Holstein steers.

The effect of appetite regulatory hormone cholecystokinin (CCK) on the secretions of oxyntomodulin (OXM) and ghrelin, and the effect of ghrelin on the secretions of CCK and OXM were studied in ruminants. Eight Holstein steers, 7 months old, 243 ± 7 kg body weight (BW), were arranged in an incomplete Latin square design (8 animals × 4 treatments × 4 days of sampling). Steers were intravenously injected with 10 µg of sulfated CCK-8/kg BW, 20 µg of acyl ghrelin/kg BW, 100 µg of des-acyl ghrelin/kg BW or vehicle.

Glucagon-like peptide-1 inhibits insulinotropic effects of oxyntomodulin and glucagon in cattle.

Oxyntomodulin (OXM), glucagon, and glucagon-like peptide-1 (GLP-1), peptide hormones derived from the glucagon gene, play an important role in glucose homeostasis. The insulinotropic action of these three homologous peptides has been well documented in monogastric animals. However, information on the relationships among these peptides in insulin-releasing action, specifically in ruminants, is still insufficient.

Sulfated gastrin stimulates ghrelin and growth hormone release but inhibits insulin secretion in cattle.

This study was designed to determine the effects of gastrin on the circulating levels of ghrelin, growth hormone (GH), insulin, glucagon and glucose in ruminants. Two experiments were done in eight Holstein steers. Animals were randomly assigned to receive intravenous bolus injections: (1) 0.

Oxyntomodulin increases the concentrations of insulin and glucose in plasma but does not affect ghrelin secretion in Holstein cattle under normal physiological conditions.

Ghrelin, the natural ligand of the growth hormone secretagogue receptor (GHS-R1a), has been shown to stimulate growth hormone (GH) secretion. Regulation of ghrelin secretion in ruminants is not well studied. We investigated the effects of oxyntomodulin (OXM) and secretin on the secretions of ghrelin, insulin, glucagon, glucose, and nonesterified fatty acids (NEFA) in pre-ruminants (5 wk old) and ruminants (10 wk old) under normal physiological (feeding) conditions.

Involvement of endothelin B receptors in the endothelin-3-induced increase of ghrelin and growth hormone in Holstein steers.

The present study was designed to determine the dose-dependent effects of endothelin-3 (ET-3) on the secretion of ghrelin and growth hormone (GH) and characterize the receptors involved in these effects. Eight Holstein steers were randomly assigned to receive intravenous bolus injections of vehicle (0.1% bovine serum albumin in saline), bovine ET-3 (0.

Endogenous ghrelin released in response to endothelin stimulates growth hormone secretion in cattle.

The purpose of this study was to evaluate whether circulating ghrelin and growth hormone (GH) concentrations in cattle are regulated by endothelin-1 (ET-1), endothelin-3 (ET-3), and secretin. Six Holstein steers (242+/-1 d old, 280.5+/-4.