Leptin gene expression in subcutaneous adipose tissue of Holstein dairy cattle using Real Time PCR

 In dairy cattle, the increase in milk yield has been accompanied by a more negative energy balance during early lactation and a decrease in fertility. As the hormone leptin is involved in regulation of nutritional status and reproductive function, this hormone is an interesting protein to investigate during the periparturient period in dairy cattle when many changes take place both in energy metabolism and reproductive physiology. The aim of this research was to study leptin gene expression in adipose tissue of Holstein dairy cattle.   Tissue sampling from subcutaneous adipose tissue of 20 Holstein cattle on the 20th day of lactation, with the same gestational age (second pregnancy) and mean body weight of 680 ± 80 kg was performed and RNA was extracted. Extracted RNA were immediately stored at -80°C.The Quality and quantity of RNA were evaluated and cDNA was synthesized and Real Time PCR was performed. PCR Products were electrophoresed on 2% agarose gel and were evaluated level of gene expression in the studied tissue.   Results showed that the leptin gene was expressed in the subcutaneous adipose tissue. These results may show that leptin plays a particular role in fat metabolism.   During the periparturient period the cow mobilizes her fat reserves (i.e. adipose tissue) and it appears that all her energy is going to the production of milk, and that other processes like reproduction and immunity, get a lower priority. Because fertility, just as milk production, is also an economically important trait, fertility should be considered as part of a dairy cattle breeding program. Generally, further studies are needed to clarify role of leptin in the physiology of fat metabolism and other materials. This would help us to better understand the mechanisms for the known effect of nutritional factors and body fatness on various functions.