Studies on the acidophilic cells of the anterior pituitary in the fowl

1) Two types of the acidophilic cells, deep α and V cells (named by the author), have been apparently demonstrated by using author's two staining methods (Table 1.) and Heidenhain's azan technique, after fixing by GOLDBERG and CHAIKOFF'S ('52) method. The anterior pituitary of the fowl is divided into two cytologically distinct regions……cephalic and caudal lobe respectively. V cells are mainly distributed in the cephalic, while deep α cells are in the caudal lobe. The results of comparison of the reports of previous investigators in the fowl pituitary with two cell types described above are as follows: The deep α cell is identified to α (KATO & NISHIDA, '35), deep staining acidophil (RAHN, '39, RAHN & PAINTER, '41), A1 (PAYNE, '42, '43, '46), A1 or dark staining acidophil (WINGSTRAND, '51), caudal acidophil (WILSON, '52) and acidophil of caudal lobe (YASUDA, '53) while the V cell is the same as light staining acidophil (RAHN, '39, RAHN & PAINTER, '41), A2 (WINGSTRAND, '51), cephalic acidophil (WILSON, '52), and nearly as α (KATO & NISHIDA, '53), A2(PAYNE, '42, '43, '46) and acidophil of cephalic lobe (YASUDA, '53)2) Compared the V cell with the deep α cell, even under low magnification, the differences of their distribution, morphology and staining reaction are noticeable, and no transitional forms are observed between the two. In morphological appearances and staining reaction, the deep α cell corresponds to the ordinary acidophil of the mammalian pituitary (Fig. 2). The V cell is similar to the deep α cell, at the points of their nuclear and cytoplasmic characters, (Fig. 3). But the V cell has more chromophobic character and smaller size than those of the deep α cell. The granules of the V cell are fine and coarse, and take light purple to violet when stained by the author's Goldberg and Severinghaus staining method. And these granules have affinity for both acid and basic dyes. This is the reason why the author named this cells "V". Therefore, the V cell could not be homologus to the ordinary acidophil of the mammals. In this study, though it could not be clearly determined, the V cell is classified under the category of the acidophilic cells, according to the previous investigators.3) In the anterior pituitaries of the dog (GOLDBERG & CHAIKOFF, '52), cattle, goat and pig (YAMAOKA, '54), two types of the acidophils (alpha and epsilon) were differentiated. However, in the fowl two types of the cells could not be apparently demonstrated from deep α cells. On the other hand, the V cell (PAYNE'S A2) in the fowl is not homologus to DAWSON'S carmine cell. They are quite different from one another from the view point of the morphology, staining reaction, distribution and cytogenesis. It is difficult to believe that the deep α cell in the fowl clearly identifies with the carmine cell, because the ordinary acidophil of the mammalian pituitary corresponds to the deep α cell, while the carmine cell was distinctly appeared at the times of the post-coitus in female rabbits and cats, and was presented in extraordinarily large numbers in the cat's pituitary during the last week of pregnancy and early lactation period (FRIEDGOOD & DAWSON, '38, '40, '42, WHITE, '49)4) Although the two cell types are limited in the main portions of the caudal and cephalic lobe, in the transitional and peripheral portion of the gland, the deep α and V cell are often seen (Fig. 1, B-F), 5) In this study, it was found that the caudal lobe of the fowl resembles most closely to the anterior pituitary of the mammals as already repored by RAHN and PAINTER ('41). It is the most interesting problem to datermine where portion is homologous as compared the cephalic lobe of the fowl with the pituitaries of other vertebrates.