Leptin receptors in the adrenal medulla of the rat
GY Cao, RV Considine… - American Journal of …, 1997 - journals.physiology.org
GY Cao, RV Considine, RB Lynn
American Journal of Physiology-Endocrinology and Metabolism, 1997•journals.physiology.orgLeptin is the protein product of the recently cloned obesity gene. Leptin receptor mRNA is
found in a number of central and peripheral locations. The hypothalamus is a presumed site
of action. However, little is known about the specific locations of the receptor in peripheral
organs. Epinephrine has potent anorectic effects and can cause weight loss by a variety of
mechanisms. Excretion of epinephrine is reduced in the ob/ob mouse, which lacks leptin,
suggesting an effect by leptin on the adrenal medulla. In the current study, the presence of …
found in a number of central and peripheral locations. The hypothalamus is a presumed site
of action. However, little is known about the specific locations of the receptor in peripheral
organs. Epinephrine has potent anorectic effects and can cause weight loss by a variety of
mechanisms. Excretion of epinephrine is reduced in the ob/ob mouse, which lacks leptin,
suggesting an effect by leptin on the adrenal medulla. In the current study, the presence of …
Leptin is the protein product of the recently cloned obesity gene. Leptin receptor mRNA is found in a number of central and peripheral locations. The hypothalamus is a presumed site of action. However, little is known about the specific locations of the receptor in peripheral organs. Epinephrine has potent anorectic effects and can cause weight loss by a variety of mechanisms. Excretion of epinephrine is reduced in the ob/ob mouse, which lacks leptin, suggesting an effect by leptin on the adrenal medulla. In the current study, the presence of the leptin receptor was identified on epinephrine-secreting cells in the adrenal medulla. Immunohistochemical studies found dense leptin receptor-like immunoreactivity in the adrenal medulla with no labeling in the adrenal cortex. Double immunofluorescent labeling confirmed that the leptin receptor was present on cells that were phenylethanolamine N-methyltransferase-like immunoreactive and therefore were epinephrine-secreting cells. Leptin receptor mRNA in the adrenal medulla was detected by reverse transcriptase-polymerase chain reaction, with the majority of the mRNA coding for the short isoform (Ob-Ra) of the receptor. Finally, autoradiography was performed using 125I-labeled leptin; specific binding was found in the adrenal medulla, with no specific binding in the adrenal cortex. These results suggest that leptin may have a direct effect on epinephrine-secreting cells in the adrenal medulla. Epinephrine may play a role in mediating the effects of leptin to reduce body weight.
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