Forms a channel that mediates water and glycerol transport across cell membranes at neutral pH (PubMed:9405233, PubMed:11952783, PubMed:30423801, PubMed:30420639). The channel is also permeable to urea (PubMed:9405233). Plays an important role in body energy homeostasis under conditions that promote lipid catabolism, giving rise to glycerol and free fatty acids. Mediates glycerol export from adipocytes. After release into the blood stream, glycerol is used for gluconeogenesis in the liver to maintain normal blood glucose levels and prevent fasting hypoglycemia. Required for normal glycerol reabsorption in the kidney (By similarity). Inhibited by mercury ions (PubMed:9405233). Fully active at pH 6.5 to 7.5. Activity decreases with decreasing pH. Inactive at pH 5.5 (PubMed:30423801, PubMed:30420639). Homotetramer (Probable). Interacts (via N-terminus) with PLIN1 (PubMed:27832861). Internalized from the cell membrane in response to catecholamine-induced activation of PKA; detected on intracellular membranes and colocalizes with lipid droplets (By similarity). Colocalizes with PLIN1 in adipocytes, probably on lipid droplets (PubMed:27832861). Detected in the sperm head (at protein level) (PubMed:28042826). Detected in white adipose tissue (PubMed:9405233). Aquaporins contain two tandem repeats each containing three membrane-spanning domains and a pore-forming loop with the signature motif Asn-Pro/Ala-Ala/Ser (NPA). Genetic variations in AQP7 are responsible for changes in glycerol release during exercise and define the glycerol quantitative trait locus (GLYCQTL) [MIM:614411]. Belongs to the MIP/aquaporin (TC 1.A.8) family.