Strain-differences between C3H and C57BL mice were studied in prolactin (LTH) cells of the anterior pituitary of diestrus females by morphometric techniques with an electron microscope.
The population of L TH-cells was higher in C3H. The size of the LTH-cells was larger in C3H, but the nucleus showed no significant difference in size. The area of secretory granules was markedly larger in C3H, not only absolutely but also relatively compared to the area of the cytoplasm, although the spaces occupied by the Golgi apparatus and rough endoplasmic reticulum showed no strain-differences. The mitochondrial area was absolutely but not relatively larger in C3H. The lysosomal area and number of exocytotic figures of secretory granules were not significantly different between the C3H and C57BL strains.
The above results suggest that the secretory activity of prolactin cells of the anterior pituitary may be higher in C3H than in C57BL strain mice.