Cytology and histochemistry of the pituitary gland of the five-striped palm squirrel, Funambulus pennanti (Wroughton).

The cytology and cytochemistry of the pitiutary gland of the palm squirrel Funambulus pennanti during different phases of reproductive activity are described. Two types each of basophils and acidophils are recognized. The basophils include gonadotrophs and thyrotrophs and acidophils include orangeopils and carminophils. The gonadotrophs which are ovoid, coarsely granulated and mainly located on the sinusoidal borders of the lateral halves of the pars anterior are more numerous in males than in females. They are PAS-positive and AF-negative. They cannot be distinguished tinctorially into FSH and LH secreting cells as in the pituitary of the rat. The thyrotrophs which are large, rounded or polyhedral, finely granulated cells are confined to the antero-median zone of the pars anterior. They are PAS and AF-positive. The basophils can be tinctorially differentiated by the performic acid-alcian blue-PAS-orange G staining in which the gonadotrophs are stained purple and the thyrotrophs are red. The acidophils are differentiated tinctorially into two types. The orangeophils or STH secreting cells are small, rounded, and coarsely granulated. Carminophils or LTH secreting cells which appear in the pituitaries of females in early pregnancy and increase in number during later pregnancy and lactation, are large and coarsely granulated. The acidophils are specifically stained with mercury-bromphenol blue.