Quantitative studies by electron microscopy on the sex-difference and the change during the oestrous cycle in the mouse anterior pituitary.

Sex-differences and changes during the oestrous cycle were quantitatively studied by electron microscopy in the mouse anterior pituitary. Sex-difference: The population of STH-cells and gonadotrophs showed a higher value in males than in females, while that of LTH-cells was lower in males. The population of TSHand ACTH-cells was a little higher in males. Chromophobes revealed no sex-difference in the population. When the volume of adenohypophysial cells was compared, none of the types of cells mentioned above showed any difference between males and dioestrus females. STH-cells and gonadotrophs of oestrus females were, however, smaller in size than those of males and LTH-cells were slightly larger in females. Changes during the oestrous cycle: The population of STH-cells, LTH-cells, TSH-cells and chromophobes showed a slight fluctuation, while the other types of cells revealed no