Question

MSH of pars intermedia of pituitary causes in lower vertebrates

• A. Darkening of skin
• B. Light colouration of skin
• C. Both A and B
• D. None of the above

Answer 1

The correct option is A Darkening of skin

An area which makes the boundary between an anterior and posterior lobes of the pituitary is called as pars intermedia. It is made up of three distinct cells such as basophils, chromophobes, and cysts with colloid. In humans, It produces melanocyte-stimulating hormone or MSH which causes the release of melanin pigment in skin melanocytes (pigment cells). But in lower vertebrates (fish, amphibians), MSH from the pars intermedia causes darkening of the skin and response to changes in the background color. This color change is due to MSH stimulating the dispersion of melanin pigment in dermal (skin) melanophore cells. Thus, the correct answer is option A.