Synthesis and Storage of Hormone
The synthesis and storage of hormone depends on the nature of the hormone. Steroid hormones are secreted in diffuse molecular form and usually accumulate in the cell as clear lipid droplets or may sometimes be bound to the membrane as lipids-protein aggregate. Hormones based on amino acids are packaged in membrane bound vesicles that are later liberated in extracellular space. The duration of storage of a hormone within a secretory tissue also varies.
Steroid hormones appear to diffuse out of the cells across the membrane (being lipid soluble) in a matter of minutes after synthesis. Secretory residues of most endocrine cells, however, are held till they are given the signal to be released. Thyroid hormone is secreted into extracellular spaces of the cells called follicles and can be stored for several months.