Diminished function of the somatotropic axis in older reproductive-aged women.

Circulating GH and insulin-like growth factor-I (IGF-I) levels in adults generally fall with age. Studies in aging women have rarely controlled for menstrual cycle stage or status or body mass index. We hypothesized that GH and IGF-I levels in reproductive-aged women fall with age despite the stimulatory effects of endogenous estradiol (E2). Eight older reproductive-aged women (aged 42-46 yr) with regular menses, of normal weight, and in good health were compared to a group of eight young control subjects (aged 19-34 yr). Daytime frequent blood sampling was performed in the early follicular phase of the menstrual cycle to characterize pulsatile GH and LH concentrations. Pooled samples were also analyzed for IGF-I, E2, progesterone, and FSH levels. Older reproductive-aged women had lower 12-h integrated daytime GH concentrations (mean +/- SE, 171 +/- 35 vs. 427 +/- 130 micrograms min/L; P = 0.036) than younger controls and a strong trend for lower IGF-I levels (22.7 +/- 2.1 vs. 31.3 +/- 3.5 nmol/L; P = 0.055) than younger controls despite having higher circulating E2 on the day of sampling (368 +/- 51 vs. 167 +/- 20 pmol/L; P = 0.002). We conclude that older reproductive-aged women have lower daytime GH concentrations than younger controls despite having higher E2 levels on the day of sampling and overall normal gonadal hormone parameters.

Gonadotropin-releasing hormone agonist administration in early human pregnancy is associated with normal outcomes.

OBJECTIVE: To evaluate the reproductive outcomes of early human gestations exposed to GnRH agonist (GnRH-a). Gonadotropin-releasing hormone agonist is commonly used as an adjunct to ovulation induction regimens, and sometimes early pregnancies are inadvertently exposed to the drug. There has been concern regarding possible teratogenic effects of GnRH-a on these gestations, but there is a paucity of data regarding human subjects. DESIGN: Identified pregnancies were followed for obstetric and fetal outcomes. PATIENTS, PARTICIPANTS: Over 4 years 18 early pregnancies among 17 women were found to be exposed to GnRH-a. During the month of conception, daily injections were begun on menstrual day 22 after documenting an ovulatory P level on day 21. Gonadotropin-releasing hormone agonist was discontinued from 10 to 24 days later, immediately after pregnancy was recognized. Obstetric and fetal outcomes were ascertained by chart review and telephone follow-up with mothers. RESULTS: Five first trimester losses were observed in 18 hCG confirmed pregnancies for a loss rate of 28%. Thirteen pregnancies produced apparently normal babies. One normal fetus was lost at 20 weeks' gestation because of cervical incompetence. CONCLUSION: There does not appear to be an increased risk of birth defects or pregnancy wastage in human pregnancies exposed to daily low-dose GnRH-a therapy in the first weeks of gestation.

The effect of endurance exercise on bone dimensions, collagen, and calcium in the aged male rat.

Sixteen weeks of a relatively mild running program, started at 22 months of age, lowered the body weights of 26-month-old male rats to the level of 9-month-old rats and increased the weights and the collagen densities of hind limb bones to levels greater than those of 9-, 22-, and 26-month-old sedentary rats. The densities (g/cm3) and the calcium densities (mg/cm3) of the hind limb bones decreased with age and were restored to the 9-month level by training the elderly rats to run. These data suggest that exercise is capable of inducing a compensation for, or a reversal of, age-associated bone loss (osteoporosis) and restoring the bone mineral content in aged rats to the level of those of mature young adult animals.