Aqp7, an aquaglyceroporin, is a transmembrane protein that facilitates the transport of glycerol across cell membranes [1,2,3,4,5,6,7,8]. It is involved in glycerol metabolism, which is an important process connecting carbohydrate and lipid metabolism [3]. Aqp7 is present in various tissues such as adipose tissue, liver, kidney, cardiomyocytes, and skeletal muscle, playing a role in physiological functions related to these tissues [3,5,6,8]. Genetic models, like knockout mice, have been valuable for studying Aqp7's functions.

In Aqp7 knockout mice, the water permeability of the proximal straight tubule brush border membrane in the kidney was reduced, and they showed marked glyceroluria, identifying a novel pathway of glycerol reabsorption in the proximal straight tubules. Also, AQP1/AQP7 double knockout mice had reduced urinary concentrating ability compared to AQP1 solo knockout mice, indicating Aqp7's substantial contribution to water reabsorption in the proximal straight tubules [6]. In cardiomyocytes, Aqp7 deficiency increased the myocardial infarct size and apoptosis in response to ischemia, suggesting its role in preventing myocardial ischemia-related damage [5].

In conclusion, Aqp7 is crucial for glycerol metabolism and related physiological processes in multiple tissues. The use of Aqp7 knockout mouse models has revealed its role in kidney function and protection against myocardial ischemia-related damage, contributing to our understanding of diseases associated with glycerol metabolism and ischemia-related cardiac dysfunction.