Age‐Related Changes in Growth Hormone in Non‐Diabetic Women

Abstract

In non-obese women with unimpaired glucose tolerance (1,185 oral glucose tolerance tests) the serum level of growth hormone (GH) in the fifth and sixth age decades was below that in the third and fourth decades. Although obesity was associated with serum GH levels below those characteristic of non-obese women, there was no evidence of a further age-related decrease of the type observed in the non-obese subjects. The lower serum GH level in women of the later age decades may well be related to the menopause with its decrease in the serum level of estrogen. Since there is no further age-related decline in GH in obesity, it would appear that in obese premenopausal females, estrogen does not exert its usual GH-enhancing effects.

The Influence of Age on the 24-Hour Integrated Concentration of Growth Hormone in Normal Individuals*

“…This finding augments past reports that GH responsiveness to other provocative stimuli also declines with age (8,14,15). Immunostaining techniques have revealed a significant decrease in both the size and number of GH-secreting pituitary cells from youth to middle age (29).…”

“…The results of several previous studies on the effects of aging on GH secretion have lead to disparate conclusions (7)(8)(9)(10)(11)(12)(13)(14)(15). The disagreement between the reports may have been due to differing techniques for assessing GH secretion and interpretation with respect to age.…”

“…The low IC-GH level in these short patients is indicative of abnormal GH secretion (20,21). Obesity has also been associated with reduced GH secretion (8,9,13) and low IC-GH (22). Previous reports of the normal IC-GH included children and adults with short stature (1,2,17,18), who may have had deficient IC-GHs.…”

“…Thus, a number of pharmacological stimulation tests have evolved to assess the normalcy of GH secretion (5,6). Previous studies of the effect of age on GH secretion relied on GH levels from single basal specimens (7)(8)(9) or from multiple samples drawn during short periods of the day (10)(11)(12) or after stimulation (7)(8)(9)(13)(14)(15).…”