Question

$MSH$ of pars intermedia of middle pituitary is responsible for

• A. darkening of skin in lower vertebrates
• B. light colouration of skin in lower vertebrates
• C. darkening of skin in human beings
• D. both (a) and (b).

Answer 1

Answer: (A)

Pars intermedia of pituitary is the boundary between the anterior and posterior lobes of the pituitary. It contains three types of cells - basophils, chromophobes and colloid-filled cysts. This area produces melanocyte stimulating hormone or $MSH$. It stimulates the synthesis of black pigment melanin in the skin and also causes dispersion of melanin granules in the pigment cells, thereby darkening the colour in certain animals e.g., fishes, amphibians.