Does Leptin Treatment Decrease Alpha-Adrenergic Receptor Expression in Mouse Renal And Mesenteric Arteries?

Abstract

Obesity often leads to hypertension. Previous work from my lab demonstrated that the adipocyte-derived hormone leptin reduces the ability of the aorta to contract in response to adrenergic stimulation, likely due to a decreased expression of the aorta alpha-adrenergic receptors. However, it is not known whether leptin decreases the expression of alpha-adrenergic receptors in such arteries like the mesenteric and renal arteries that play a key role in the control of blood pressure. To determine whether leptin decreases alpha-adrenergic receptor expression in renal and mesenteric arteries, I infused leptin (10ug/day) by implanting subcutaneous mini-pumps in five male C57bl/6 mice. Five mice did not receive leptin and served as controls. After seven days of treatment I euthanized nine mice as one mouse died. Renal and mesenteric arteries were taken from the mice and mRNa was extracted from the arteries. Reverse Transcription (RT) was completed in order to induce the transcription of mRNA into cDNA. After checking the concentration of cDNA, real-time PCR (qPCR) conducted on the arteries revealed high CT values for a1D-receptor concluding that leptin-mediated increases in sympathetic tone decreased a1D-receptor expression. This data is supportive of my hypothesis that leptin- decreases adrenergic receptor expression in renal and mesenteric arteries.