Effect of exogenous insulin and fasting on growth hormone receptor and IGF-I expression in the pre-ovulatory follicle of ewes

Abstract

The aim of this study was to investigate the effect of fasting and exogenous insulin administration on the expression of growth hormone receptor (GHR) and IGF-I mRNA in the pre-ovulatory follicle of ewes. Fifteen ewes received an intravaginal progesterone releasing device that was removed 6 days later (day of removal 5 day 0). On day 22, the ewes were divided into three groups: (i) fasting group (n 5 5) that was fasted from day 22 to day 2; (ii) control group (n 5 5) that received a maintenance diet; and (iii) insulin group (n 5 5) that received insulin injections (0.25 IU/kg) every 12 h from day 22 to day 2 under the same diet as the control group. Follicular samples were obtained on day 2. Fasting increased plasma non-esterified fatty acids concentrations from day 21 to day 2 (P , 0.001). There was no difference ( P . 0.05) in the number of follicles, although there was a tendency for an increase in the pre-ovulatory follicle diameter for the insulin group in comparison to the control group ( P 5 0.12). Thecal GHR mRNA expression was very low and was considered insignificant. Moreover, granulosa cells GHR mRNA expression increased ( P , 0.05) in the insulin group. Expression of IGF-I mRNA was not different among groups in both tissues. In conclusion, insulin administration increases GHR mRNA but not IGF-I mRNA expression in granulosa cells of the pre-ovulatory follicle. However, fasting did not change the pattern of GHR/IGF-I mRNA expression in the pre-ovulatory follicle.

Insulin and insulin-like growth factor-1 modulate the lipolytic action of growth hormone by altering signal pathway linkages

“…Regardless, these findings are consistent with the anabolic actions of INS and IGF-1 (Caruso and Sheridan, 2011) as well as with the specific antilipolytic actions of INS in mammals. For example, INS inhibits activation of HSL in fish (Sheridan, 1994) and attenuated fasting-stimulated lipolysis in mammals to control levels (Schneider et al, 2011).…”

Análise da glicemia e de IGF-1 após laserterapia nas glândulas salivares de ratas diabéticas

“…Macro e microangiopatias e neuropatia estão dentre as principais complicações crônicas do DM. Além disso, o DM está relacionado com algumas complicações na cavidade oral, como será abordado adiante (Gayton;Hall, 1997;Borg Andersson et al, 1998;Kido et al, 2002;Mata et al, 2004;Fieffe et al, 2011;Schneider et al, 2011;Ashcroft e Rorsman, 2012;Kim et al, 2012;King, 2012; American Diabetes Association, 2012).…”

“…As complicações da hiperglicemia crônica estão relacionadas à disfunção e falência de vários órgãos, especialmente em rins, coração e olhos, além de alterações nos sistemas vascular e nervoso (Gayton;Hall, 1997;Borg Andersson et al, 1998;Mata et al, 2004;Greenspan;Gardner, 2007;Fieffe et al, 2011;Schneider et al, 2011;Ashcroft;Rorsman, 2012;Kim et al, 2012;King, 2012;American Diabetes Association, 2013). Em cavidade oral, as complicações mais comuns causadas pelo aumento da glicemia são a hipossalivação, cárie dental, mucosite e gengivite (Centers for Disease Control and Prevention, 2012;Humphrey;Williamson, 2001;Moore et al, 2001;Mata et al, 2004;Simões et al, 2008;Simões et al, 2009a;Simões et al, 2009d).…”