I think the answer to this is: Endocrine glands secrete hormones directly into the bloodstream. The hormones dissolve in plasma and travel the circulatory pathways through various body tissues, Others enter the cells bind to receptors in the cytoplasm or nucleus.
The hormones are released into the blood stream by which they travel and reach the target cells. The target cell has specific receptors which gets activated and binds to the hormone.
The hormones from the endocrine glands are secreted and transported to the target cells via bloodstream.
The plasma membrane are permeable and gets inside the cell to perform its function.
