Many other xanthine analogues constituting the adenosine receptor antagonist class have also been elucidated. Chemical syntheses of spironolactone and its analogues and derivatives have been described and reviewed. GnRH modulators are also commonly known as GnRH analogues. A variety of derivatives and analogues are known. Since the discovery of CPT many analogues have been synthesized. Synthetic zeolites hold some key advantages over their natural analogues. This would allow for the possibility of exotic nihonium compounds without lighter group 13 analogues. Initial therapeutic antibodies were murine analogues (suffix "-omab"). Use of vasopressin analogues for esophageal varices commenced in 1970. All of these analogues are thermodynamically unstable. Their chemical properties are distinct from the properties of their singlet analogues. In IUPAC's nomenclature, fully saturated analogues of fullerenes are called "fulleranes". The germanes are less volatile and less reactive than their corresponding silicon analogues. Some of the organisms that contain palytoxin or its close analogues are listed below. This resulted in the discovery of a number of colchicine analogues.