Levels of alpha-inhibin in aging female mice.
alpha-inhibin was immunocytochemically localized in granulosa cells of different stages of developing follicles, freshly formed corpora lutea, and scattered interstitial cells (pigmented or ceroid cells) in ovaries of 6-, 14-, and 23-25-mo-old C57BL/6NNia mice. Developing follicles exhibited the greatest amount of staining. Quantitation of the stain using an image analysis system indicated the staining intensity within ovarian follicles of 14-mo-old mice was greater than that in 23-25-mo-old mice. The levels of plasma alpha-inhibin and estradiol (E2) decreased with age. The number of follicles present in ovaries of middle-aged mice was comparable to those of 6-mo-old mice, yet plasma levels of FSH were significantly higher than those of 6-mo-old mice. This may be due to an age-related loss in the sensitivity of the hypothalamus and/or pituitary of middle-aged mice to ovarian hormones. In contrast, ovaries of 23-25-mo-old mice contained few antral follicles and consequently produced little alpha-inhibin. There appeared to be little negative feedback regulation of FSH secretion in 23-25-mo-old mice as a result of age-related ovarian impairments. This study supports an earlier hypothesis from our laboratory [Biol Reprod 1985; 32:989-997] that the primary defect(s) limiting age-related reproductive performance in mice appears to reside within the hypothalamo-hypophyseal axis, whereas secondary defects arise from the ovary.
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Department of Anatomy & Neurosciences, University of Texas Medical Branch, Galveston 77550.
Collins
T J
TJ
Parkening
T A
TA
D000375:Aging / Q000378:metabolism*; D000818:Animals; D003338:Corpus Luteum / Q000378:metabolism; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006107:Granulosa Cells / Q000378:metabolism; D007150:Immunohistochemistry; D007265:Inhibins / Q000097:blood / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D010053:Ovary / Q000378:metabolism*
D004958:Estradiol; D007265:Inhibins; D005640:Follicle Stimulating Hormone