scholarly journals Leptin Stimulates Prolactin mRNA Expression in the Goldfish Pituitary through a Combination of the PI3K/Akt/mTOR, MKK3/6/p38MAPK and MEK1/2/ERK1/2 Signalling Pathways

2017 ◽  
Vol 18 (12) ◽  
pp. 2781 ◽  
Author(s):  
Aifen Yan ◽  
Yanfeng Chen ◽  
Shuang Chen ◽  
Shuisheng Li ◽  
Yong Zhang ◽  
...  
1992 ◽  
Vol 9 (3) ◽  
pp. 273-281 ◽  
Author(s):  
A. Stephanou ◽  
N. J. Sarlis ◽  
R. A. Knight ◽  
S. L. Lightman ◽  
H. S. Chowdrey

ABSTRACT Adjuvant arthritis (AA) in the rat leads to chronic stimulation of the hypothalamic-pituitary-adrenal (HPA) axis and the loss of its diurnal rhythmicity. We have investigated the effects of adrenalectomy (ADX) and different levels of corticosterone replacement upon plasma ACTH levels and anterior pituitary pro-opiomelanocortin (POMC), GH and prolactin mRNAs during the development of AA. In control ADX animals, we observed the negative feedback effects of exogenous corticosterone on plasma ACTH and anterior pituitary POMC mRNA. In the ADX animal with AA, however, the increased POMC mRNA which was observed was not reduced by exogenous corticosterone on day 7 of AA, although the negative feedback effect of corticosterone on plasma ACTH was intact. On day 14, however, even high dose corticosterone replacement failed to have a significant feedback effect on the raised levels of plasma ACTH. In control ADX animals, corticosterone replacement resulted in increased anterior pituitary GH mRNA and reduced prolactin mRNA. In contrast, in ADX animals with AA, GH mRNA was reduced and there was a further decrease in prolactin mRNA. In these animals, corticosterone replacement did not affect GH or prolactin mRNA expression. These data demonstrate a disruption of the normal mechanisms underlying feedback inhibition of the HPA axis by glucocorticoids during AA. Similarly, the glucocorticoid-dependent regulation of GH and prolactin mRNA expression is altered in AA.


2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Yangchun Cao ◽  
Kai Liu ◽  
Shimin Liu ◽  
Long Guo ◽  
Chuanjiang Cai ◽  
...  

This study aimed to investigate the effects of isoleucine (Ile) on the synthesis and secretion of digestive enzymes and cellular signalling in the pancreatic tissue of dairy goats. The pancreatic tissues were incubated in buffer containing 0, 0.40, 0.80, and 1.60 mM Ile. High levels of Ile significantly increased the buffer release and total concentration of ɑ-amylase in the tissues (P < 0.001). The total trypsin and chymotrypsin concentrations in each of the Ile groups were significantly higher than those in the control group (P < 0.05); however, lipase was not affected. High levels of Ile significantly increased ɑ-amylase mRNA expression (P < 0.001) but had no effect on the mRNA expression of trypsin, chymotrypsin, or lipase. Ile did not affect S6K1 phosphorylation levels. High levels of Ile significantly increased the expression of the γ isoform of 4EBP1 (P < 0.001), which indicated that the phosphorylation of 4EBP1 was significantly increased. The phosphorylation level of eEF2 gradually decreased with the addition of Ile (P < 0.001). These results suggested that high doses of Ile can regulate the excretion of enzymes, especially ɑ-amylase, in the pancreatic tissues of dairy goats by modulating mTOR signalling, and this regulation is independent of the mTOR-S6K1 pathway.


2011 ◽  
Vol 106 (8) ◽  
pp. 1173-1181 ◽  
Author(s):  
Aramsri Meeprom ◽  
Weerachat Sompong ◽  
Wannaporn Suwannaphet ◽  
Sirintorn Yibchok-anun ◽  
Sirichai Adisakwattana

Recent evidence strongly supports the contention that grape seed extract (GSE) improves hyperglycaemia and hyperinsulinaemia in high-fructose-fed rats. To explore the underlying molecular mechanisms of action, we examined the effects of GSE on the expression of muscle proteins related to the insulin signalling pathway and of mRNA for genes involved in the adiponectin signalling pathway. Compared with rats fed on a normal diet, high-fructose-fed rats developed pathological changes, including insulin resistance, hyperinsulinaemia, hypertriacylglycerolaemia, a low level of plasma adiponectin and a high level of plasma fructosamine. These disorders were effectively attenuated in high-fructose-fed rats supplemented with GSE. A high-fructose diet causes insulin resistance by significantly reducing the protein expression of insulin receptor, insulin receptor substrate-1, Akt and GLUT4, and the mRNA expression of adiponectin, adiponectin receptor R1 (AdipoR1) and AMP-activated protein kinase (AMPK)-α in the skeletal muscle. Supplementation of GSE enhanced the expression of insulin signalling pathway-related proteins, including Akt and GLUT4. GSE also increased the mRNA expression of adiponectin, AdipoR1 and AMPK-α. In addition, GSE increased the mRNA levels of glycogen synthase and suppressed the mRNA expression of glycogen synthase kinase-3-α, causing an increase in glycogen accumulation in the skeletal muscle. These results suggest that GSE ameliorates the defective insulin and adiponectin signalling pathways in the skeletal muscle, resulting in improved insulin resistance in fructose-fed rats.


2012 ◽  
pp. 481-488 ◽  
Author(s):  
P. ČEJKOVÁ ◽  
V. CHROMÁ ◽  
M. ČERNÁ ◽  
M. MARKOVÁ ◽  
J. MAREK ◽  
...  

Our study explored the role of extrapituitary prolactin (PRL) and toll-like receptors (TLR)2 and TLR4 in defense reaction of immune system to bacterial infection. Forty-two patients diagnosed with sepsis were recruited and blood samples were withdrawn after patients’ admission to hospital, after the end of acute phase of sepsis and after the sepsis has been resolved, respectively. Seventeen patients died of sepsis; thus, only one sample collected just before death could be processed. PRL and TLR2/4 mRNA levels were measured in CD14+ blood monocytes by QPCR and PRL -1149 G/T SNP genotyped. The TLRs mRNA expression was markedly elevated in all patients groups in comparison to healthy controls mRNA levels; the highest upregulation of monocytic TLR2 in sepsis (16.4 times, P<0.0001) was detected in patients who did not survive septic complications. PRL mRNA expression in monocytes from non-survivors tended to be lower (4.5 fold decrease, P=NS) compared to control levels and it was 6.2 times reduced compared to PRL mRNA expression in second blood sample from survivors (P<0.05). The PRL -1149 G/T SNP had no effect on PRL mRNA response during sepsis. Our data suggest that increased prolactin mRNA expression in monocytes is associated with better outcome and improved survival rate in sepsis with no apparent effect of PRL -1149 G/T SNP on monocytic prolactin response.


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