Long-Term Changes in Gastrin, Cholecystokinin and Insulin in Response to Oxytocin Treatment

Abstract

The present study was designed to investigate how repeated injections of oxytocin influence plasma levels of vagally controlled hormones such as gastrin, cholecystokinin (CCK), insulin and somatostatin, as well as of endogenous oxytocin and glucose. Since oxytocin may enhance the activity of centrally located α₂-adrenoreceptors, a second aim of this study was to explore whether these receptors are involved in the effects. For this purpose, oxytocin (1.0 mg/kg) or NaCl was given subcutaneously (s.c.) once a day during 5 days to male rats. Rats were decapitated 1, 3 and 10 days after the last injection, blood was collected and hormone levels were radioimmunoassayed. The oxytocin treatment caused an elevation of plasma levels of oxytocin 1 day (p < 0.05) but not 3 and 10 days after treatment. Gastrin levels were decreased on day 1, 3 and 10 (ANOVA; p < 0.01). In addition, both insulin and CCK levels were decreased in response to the oxytocin treatment when measured 3 and 10 days after the last injection (ANOVA; insulin p < 0.01, CCK p < 0.05). When the α₂-adrenoreceptor agonist clonidine (2.5 µg/kg intracerebroventricularly) was administered 3 days after the 5-day treatment period with oxytocin or saline, plasma levels of insulin and CCK increased significantly (p < 0.05) in the oxytocin-treated rats, when compared to saline-treated controls receiving clonidine only. No change in glucose or somatostatin levels was found in response to the oxytocin treatment. In conclusion, these results show that oxytocin induces long-lasting changes in plasma levels of gastrin, CCK and insulin, without affecting somatostatin or glucose levels. These effects may be mediated by changes in vagal nerve activity.

Oxytocin effects on experimental skin wound healing

“…This might be due to the fact of less concentrations of tumor necrosis factor-α and interleukin-6, a decreased rate of apoptosis, diminished neutrophil recruitment, and less lipid peroxidation in the different organs under investigation [51]. In this context, OXY has been described to act as an anti-inflammatory agent via the increase of corticosterone levels even after a single OXY injection [7,14,15,55] as well as an antioxidant via the regulation of the oxidant-antioxidant status [52,53,56,57]. Furthermore, the anti-inflammatory OXY action was recently been reported to be a direct neutrophil-dependent mechanism, ameliorating the oxidative organ damage [52,58].…”

“…Male homozygous SKH-1-h hairless mice (12)(13)(14)(15)(16) weeks old) with a body weight (bw) of 30-40 g were used in the study. The animals were housed in standard laboratories with a 12 h light-dark cycle and had free ad libitum access to standard laboratory food and water.…”

“…For the here presented study we orientated us in what was given in previously done work in the context of oxytocin Petersson et al 1999;Iseri et al 2005;Erbas et al 2014;Agren & Lundeberg 2002a,b;Vitalo et al 2009;Uvnäs-Moberg et al 1995) and its selective oxytocin receptor antagonist atosiban Simsek et al 2011;Alizadeh et al 2010;Zhang et al 2007;Petersson et al 1998). In a different study by Poutahidis and colleagues mice were injected intraperitoneally every 4-6 hours with 15 units/mouse of oxytocin.…”

“…The above mentioned points have been added to the discussion section of the revised version of the manuscript marked by red font and underlining and reads as follows: "For the here presented study we orientated us in the dosing regimens of previously done work in the context of oxytocin Petersson et al 1999;Iseri et al 2005;Erbas et al 2014;Agren & Lundeberg 2002a,b;Vitalo et al 2009;Uvnäs-Moberg et al 1995) and its selective OXY receptor antagonist atosiban Simsek et al 2011;Alizadeh et al 2010;Zhang et al 2007;Petersson et al 1998). The treatment with the OXY antagonist atosiban elevates oxidative stress in the hearts of newborn rats , abolished the cardiopreconditioning effect of OXY (Alizadeh et al 2010) and reversed the OXY effect on gastric ischemia-reperfusion injury ).…”

“…less stress), which were associated with overall better healing performances [12,13]. If applied repetitively, the effects on other transmitter systems could demonstrate long-lasting effects that show interaction in both growth and healing actions [7,[12][13][14]. Herein, it could be demonstrated that OXY application in rats leads to an acute antiinflammatory response [15].…”