The effect of age on the number of pituitary cells immunoreactive to growth hormone and prolactin.

The results of a combined immunocytochemical, morphometric, and clinicopathologic analysis of growth-hormone-producing and prolactin-producing pituitary cells in 28 subjects ranging in age from 16 to 90 are reported. There was a significant age-related decline in the number and size of growth-hormone-producing cells, which was most marked in the transition from youth to middle age. There was also a significant age-related decline in the number of pituitary parenchymal cells but not in pituitary weight. Prolactin cells did not show a significant decline in number with age.