Experimental technique: the use of parabiosis to evaluate hormone functioncoleman and his colleagues used a technique called parabiosis to evaluate if the products of the ob and db genes were involved in hormonal regulation of appetite and body fat. in parabiosis, two closely related animals are surgically joined from the shoulder to the pelvis. new capillaries grow between the two organisms, resulting in a shared circulatory system. however, not all compounds that circulate in the blood are exchanged between the two individuals. long-lived (slowly metabolized) compounds such as hormones are exchanged. short-lived (rapidly metabolized) compounds such as glucose and fatty acids are not exchanged. consider a db/db mutant and a wild-type mouse that will be joined by parabiosis. the db/db mutant has greatly elevated levels of both appetite-suppressing hormone and glucose because of its inability to suppress its appetite. in contrast, the wild-type mouse has normal levels of both hormone and glucose.