2. Posterior Lobe : The posterior pituitary comprises the posterior lobe of the pituitary gland. It consists mainly of axons extending from the supraoptic and paraventricular nuclei of the hypothalamus. Posterior lobe of the pituitary releases two hormones into the circulation, both synthesized in the hypothalamus.

(a) Vasopressin: Vasopressin is also known as arginine vasopressin , argipressin or antidiuretic hormone. Vasopressin is a peptide made up of 9 amino acids. Vasopressin acts on the collecting ducts of the kidney to facilitate the reabsorption of water into the blood and reduce the volume of urine formed. Deficiency of vasopressin leads to diabetes insipidus, a condition where there is excessive loss of urine and hypernatremia. High levels of vasopressin secretion may lead to hyponatremia.

(b) Oxytocin : Oxytocin is a mammalian hormone that acts mainly as a neuromodulator in the brain. Oxytocin is a peptide of 9 amino acids. Oxytocin is best known for its roles in sexual reproduction, in particular during and after childbirth. It acts on certain smooth muscles stimulating contractions of the uterus at the time of birth and release of milk when the baby begins to suckle.

3. Intermediate lobe: The intermediate lobe is the boundary between the anterior and posterior lobes of the pituitary. It consists of three types of cells - basophils, chromophobes, and colloid-filled cysts.

The intermediate lobe of the pituitary secretes the melanocyte-stimulating hormone. The melanocyte-stimulating hormone stimulates the production and release of melanin by melanocytes present in the skin and hair.  

Pheromones:

Pheromones are chemicals that are secreted in our sweat and other bodily fluids which release neurotransmitters that directly modify the behaviour of the opposite sex, such as triggering sexual excitement. The word ‘pheromone' comes from the Greek word ‘phero' which means "to bear" and ‘hormone' which means "impetus". There are alarm pheromones , food trail pheromones , sex pheromones , and many other pheromones affect behaviour or physiology. The first pheromone that was identified in 1956 was a powerful sex attractant for silkworm moths. The least amount of it made male moths beat their wings madly in a flutter dance. The term "pheromone" was introduced by Peter Karlson and Martin Luscher in 1959. Strong pheromones can be a warning signal to predators to stay away or it can be also a signal that the prey animal is indigestible. Certain plants emit alarm pheromones when grazed upon by herbivorous animals resulting in tannin production in neighbouring plants. These tannins make the plants less appetizing.