Biology Reference
In-Depth Information
type 2 diabetes (Ozcan et al.
2004
; Cnop et al.
2012
) and may be the molecular link
between these conditions.
Taurine (TAU) is a sulfur-containing amino acid know to exert positive effects upon
beta cell function and glucose homeostasis (Nakaya et al.
2000
; Tsuboyama-Kasaoka et al.
2006
; Carneiro et al.
2009
; Ribeiro et al.
2009
; Ribeiro et al.
2012
). Plasma TAU levels are
reduced in plasma of protein-restricted dams and their fetuses (Cherif et al.
1998
) . It was
previously reported by our group that TAU supplementation to malnourished rats normal-
ized insulin secretion and glucose tolerance and increased protein expression of SERCA3
in pancreatic islets (Batista et al.
2012
), suggesting improved islet ER function. Here we
assessed the effects of TAU supplementation upon insulin secretion and ER stress markers
in pancreatic islets and in the liver from malnourished mice.
14.2
Methods
14.2.1
Animals and Groups
All experiments were approved by the ethics committee at UNICAMP. The studies
were carried out on 21-day-old male Swiss mice obtained from the breeding colony
at UNICAMP and maintained at 22 ± 1°C, on a 12-h light-dark cycle, with free
access to food and water. The mice were distributed into four groups: mice that
received a diet containing 17% of protein without (NP) or with 2.5% of TAU in their
drinking water (NPT), or mice submitted to an isocaloric diet containing 6% of
protein (low-protein diet) without (LP) or with TAU supplementation (LPT). During
experimental period, body weight was monitored weekly. Diet composition was
previously reported (Filiputti et al.
2008
) .
14.2.2
Plasma Insulin
At the end of the diet and supplementation period, anesthetized fed mice were
decapitated and their blood was collected and centrifuged at 10,000 rpm for 5 min
at 4°C. Plasma was collected and stored at −20°C. Plasma insulin was measured by
radioimmunoassay (RIA; as previously reported by Ribeiro et al.
2010
) .
14.2.3
Islet Isolation and Static Insulin Secretion
Islets were isolated by collagenase digestion of the pancreas. For static incubations,
five islets from each group were first incubated for 30 min at 37°C in Krebs-
bicarbonate (KBR) buffer with the following composition: NaCl 115 mmol/L, KCl
5 mmol/L, CaCl2 2.56 mmol/L, MgCl2 1 mmol/L, NaHCO3 10 mmol/L, and
Search WWH ::
Custom Search