Effects of aging on the human ovary: the secretion of immunoreactive alpha-inhibin and progesterone.

Objective: To investigate the changes induced by age in the function and secretory pattern of the human ovary. Immunoreactive alpha-inhibin, E2, and P secretion in vivo and in vitro have been compared in two different populations.
Design: Prospective study. Women undergoing IVF-ET were divided into two groups according to age: group 1 (32.0 +/- 0.7 years; mean +/- SEM) and group 2 (40.3 +/- 0.3 years).
Setting: In vitro fertilization program at the Instituto Valenciano de Infertilidad.
Patients: A total of 33 infertile women with regular menses, undergoing IVF-ET.
Interventions: Follicle aspiration performed by transvaginal ultrasound. Four follicles per patient were aspirated in individual plastic tubes. Granulosa-luteal cells isolated with Percoll columns and cultured in vitro up to 4 days in the presence of hCG.
Main Outcome Measures: In vitro fertilization parameters, serum levels of E2, immunoreactive alpha-inhibin, and P, as well as the secretion of immunoreactive alpha-inhibin and P by the cultured granulosa-luteal cells.
Results: Serum immunoreactive alpha-inhibin levels the day of ovum pick-up were significantly lower in group 2 compared with group 1. Incubation of cells for 96 hours showed a significantly higher ability to accumulate immunoreactive alpha-inhibin in group 1 than 2. Human chorionic gonadotropin stimulated immunoreactive alpha-inhibin production after 96 hours. Cells from younger women displayed a significantly higher ability to secrete P than cells from older women. Human chorionic gonadotropin was able to significantly stimulate P production in group 1.
Conclusions: These results confirm previous observations showing a reduced production of immunoreactive alpha-inhibin and steroids of ovaries from older women and suggest that a reduced cellular function, rather than a decrease in the follicular population, is the main mechanism by which these changes are produced.