Gene expression and hormonal regulation of adiponectin and its receptors in bovine mammary gland and mammary epithelial cells

Abstract

Although the functions of adiponectin, a differentiated adipocyte-derived hormone, in regulating glucose and fatty acid metabolism are regulated by two subtypes of adiponectin receptors (AdipoRs; AdipoR1 and AdipoR2), those in ruminants remain unclear. Therefore we examined the messenger RNA (mRNA) expression levels of adiponectin and its receptors in various bovine tissues and mammary glands among different lactation stages, and the effects of lactogenic hormones (insulin, dexamethasone and prolactin) and growth hormone (GH) on mRNA expression of the AdipoRs in cultured bovine mammary epithelial cells (BMEC). AdipoRs mRNAs were widely expressed in various bovine tissues, but adiponectin mRNA expression was significantly higher in adipose tissue than in other tissues. In the mammary gland, although adiponectin mRNA expression was significantly decreased at lactation, AdipoR1 mRNA expression was significantly higher at peak lactation than at the dry-off stage. In BMEC, lactogenic hormones and GH upregulated AdipoR2 mRNA expression but did not change that of AdipoR1. In conclusion, adiponectin and its receptor mRNA were expressed in various bovine tissues and the adiponectin mRNA level was decreased during lactation. These results suggest that adiponectin and its receptors ware changed in mammary glands by lactation and that AdipoRs mRNA expression was regulated by different pathways in BMEC.

Fibroblast growth factor 21 in breast milk controls neonatal intestine function

“…Here, we establish that FGF21 is among the endocrine factors that confer the important properties of breast milk and contribute to the maturation of the neonatal gastro-intestinal system, at least in the current rodent model. Maternal blood, rather than the mammary gland, appears to be the main source of milk FGF21; this is similar to previous findings for EGF 20 and IGF-II 21 , but contrasts with those for leptin and adiponectin 13 22 . Consistent with a previous report 23 , we observed high blood FGF21 levels in lactating dams.…”

Chemerin is a novel regulator of lactogenesis in bovine mammary epithelial cells

“…This result suggests these lactogenic hormones regulate CMKLR1 expression to modulate the regulatory effect of chemerin on genes associated with lactogenesis in mammary epithelial cells during the lactation cycle. Our previous studies showed that adiponectin expression in mammary glands decreases in the peak and late-lactation period, although adiponectin receptor 1 (AdipoR1) expression increases in the same period [28]. Serum adiponectin concentrations are higher 2e3 weeks after parturition in Holstein cows [29]; another study showed decreased plasma adiponectin protein levels at parturition with a recovery within 2 months [30].…”

Changes in circulating adiponectin and metabolic hormone concentrations during periparturient and lactation periods in Holstein dairy cows

“…2003). Our previous report showed that adiponectin mRNA levels in mammary glands were significantly lower at lactational stages than at non‐lactational stages (Ohtani et al . 2011).…”

“…Although these results may be specific in ruminants, these mechanisms are still unclear. Our previous report showed that AdipoR1 mRNA levels increased at peak lactation in bovine mammary tissues and GH and lactogenic hormones (insulin, prolactin and dexamethasone) regulated the levels of AdipoR2 mRNA expression in bovine mammary epithelial cells (Ohtani et al . 2011).…”

“…2003, 2007). In our previous study, bovine adiponectin and its receptor genes were expressed in various tissues particularly in mammary tissues, and expression levels were changed during the lactation cycle (Ohtani et al . 2011).…”