(a) : Acromegaly is caused by excess of STH (somatotropic hormone),also called growth hormone released by anterior lobe of pituitary after adolescence. The bones of the lower jaw and limbs become abnormally enlarge but the body does not attain a giant stature. Excess of thyroxine causes cretinism and myxoedema. Excess of adrenaline causes increased BMR, heart beat, excitement etc.