Changes in Hypophysis of Adult Male and Female Rats After Pregnancy Urine Extract Injections. ∗

Meyer, Leonard, Hisaw and Martin 1 demonstrated that oestrin diminishes the gonad stimulating capacity of the anterior pituitary. Inasmuch as the injection of P. U. extract into normal females increases their oestrin output, the potency of their pituitaries should thereby be diminished. Leonard 2 injected a large series of adult male and female rats with P. U. extracts† and subsequently tested their pituitaries for gonad stimulating potency by implantation into immature female mice. Pituitaries of the injected animals showed a marked decrease in gonad stimulating potency. The potency of the castrate's pituitary was not diminished by P. U. injections.

The pituitaries of 32 normal and castrate controls and injected rats, from the experiments of Dr. Leonard, were utilized for cytological study. They were fixed and stained by methods previously described. 3 As expected, marked changes were observed in the basophiles. 4 These cells in large part were depleted of their basophilic granules. Their cytoplasm appeared as clumped, yellowish masses frequently with small basophilic granular areas interspersed. The distinguishing Golgi apparatus was hypertrophied. The cytological picture suggests a cell which has been in active secretory phase. These basophiles range in size from normal basophiles down to cells little larger than chromophobes. An even more striking feature, however, is their obvious numerical increase. There is a corresponding decrease in chromophobes. If changes occur in the acidophils, they are of such character that they could be detected only by careful statistical analyses of cell size and numbers. Technical methods which do not demonstrate the Golgi region either in positive 01 negative form would make difficult an accurate separation of the chromophobes from the smaller of the atypical degranulated baso philes. The injections of P. U. extract, therefore, seem to cause both an increase of basophiles and a rapid atypical degranulation of their cytoplasm. The pituitaries of castrates injected with P. U. extract cannot be distinguished histologically from the castrate controls.