Growth Hormone Economy in Normally Cycling Women

Although it has long been recognized that the secretion of growth hormone (GH) differs between adult men and women, the mechanisms involved remain to be fully elucidated. A number of observations have suggested that the gonadal hormones in general and estrogen in particular may be primary factors subserving gender-associated differences in GH release. In premenopausal women with ostensibly intact ovarian function, both serum concentrations of GH (1) and GH secretory rates (2) are higher than those documented in men. Serum GH is reported to be relatively elevated during the periovulatory (3) and midluteal (1) phases of the human menstrual cycle, times when endogenous estrogen concentrations are increased in comparison to those measured during the early follicular phase of the cycle. Moreover, the exogenous administration of estrogen appears to be associated with alterations in serum GH concentrations. Thus, such concentrations are greater in premenopausal girls (4), premenopausal women (2), postmenopausal women (5), and men (1) treated with estrogen compared to the estrogen-deficient state.