Each granular gland consists of numerous alveoli or secretory vesicles that are surrounded by connective tissue (Hostetler & Cannon 1974; Cannon & Hostetler 1976; Alvarez et al.
The most common and "traditional" method of obtaining granular gland secretion has been a non-conservative technique that requires sacrificing the animal and subsequent mechanical and chemical processing of the skin (Roseghini et al.
Zasloff notes that the frog magainins are made throughout the animal's skin by the granular gland, which also produces neurotransmitters and hormones.
Perhaps this practice induces the frog to release magainins in the same way Zasloff has found that a shot of adrenaline will cause frogs in his laboratory to release the contents of their granular glands.
Analysis of the peptidomes of amphibian skin granular gland
secretions - an integrated functional genomic strategy (Chris Shaw, and Tianbao Chen).