MR height of the pituitary gland as a function of age and sex: especially physiological hypertrophy in adolescence and in climacterium.

Abstract

PURPOSE: To clarify the age- and sex-related changes in pituitary height. METHODS: We reviewed sagittal T1-weighted MR images in 1020 subjects to analyze the size of the pituitary gland. RESULTS: The pituitary height in female subjects (mean, 5.35 mm; SD, 1.2) was significantly greater than that in male subjects (mean, 4.93 mm; SD, 1.0). When the data were analyzed for different age ranges, sex-related differences were statistically significant only in the 10- to 19-, 20- to 29-, and 50- to 59-year-old age groups. The pituitary height peaked in the 20-to-29 age group and tended to decline with age. In female subjects, however, there was a tendency for pituitary height to increase again in the 50-to-59 age group. CONCLUSION: The pituitary height may reflect physiological neuroendocrine differences between younger and older subjects and between male and female subjects. The second increase observed in female subjects may likewise reflect high concentrations of gonadotropic hormones, apparently due to an age-related decline in circulating gonadal steroids and an increase in gonadotropin-releasing hormone.