Background
In postpartum dairy cows, dry matter intake (DMI) was dramatically decreased, resulting in the decreased plasma glucose, a negative energy balance (NEB), and negative nutrient balance. Asprosin, which is a fasting-induced glucogenic protein hormone secreted by adipose tissue, promotes plasma glucose level. However, effect of asprosin on the hepatic glucose output in primary bovine hepatocytes and plasma asprosin level in postpartum dairy cows remain not reported.
Results
Our results demonstrated that fibrillin 1 (FBN1) showed much higher mRNA expression in mammary gland and adipose tissue compared with heart, liver, spleen, lung, and kidney. The recombinant bovine His-asprosin was not found in supernatant of E. coli lysate, but present in the inclusion bodies in E. coli. The bovine His-asprosin proteins were > 90 % pure by Coomassie Blue-stained SDS-PAGE gel analysis. Asprosin enhanced (P = 0.031) the mRNA expression of PCK2 in primary bovine hepatocyte compared with control group, and FBP1 tended (P = 0.086) to be upregulated in primary bovine hepatocyte treated by Asprosin. Remarkably, glucose output was increased (P = 0.03) in primary bovine hepatocytes exposed to asprosin than control group. In addition, Asprosin can promote PKA activity in primary bovine hepatocytes, but not AKT. Asprosin was observed to be present in bovine plasma at consistent nanomolar levels. The postpartum cows exhibited (P = 0.003) much higher level of circulating asprosin compared with mid-lactation dairy cows.
Conclusions
These findings indicate that asprosin should be further considered for use as a novel therapy strategy for NEB and negative nutrient balance in postpartum period.