Immunohistochemical localization of activin A in human endometrial tissues during the menstrual cycle and in early pregnancy.
OBJECTIVE
To investigate the possible localization of activin A in human endometrial tissue.


METHODS
Human endometrial tissue was collected from 33 patients who were undergoing abdominal hysterectomy. Human decidual tissue was collected from 11 patients, who were having a therapeutic abortion. Tissue was fixed in Bouin's solution and made into paraffin sections. Tissue sections were stained with monoclonal antibodies against the inhibin/activin alpha- and betaA-subunits and activin A using an avidin-biotin-peroxidase complex technique.


RESULTS
No immunostaining with antibody against the alpha-subunit was observed in the human endometrium during the menstrual cycle or in the decidua during early pregnancy. By contrast, immunostaining for the betaA-subunit and activin A was observed in the cytoplasm of endometrial glands at all phases of the menstrual cycle and in the decidua during early pregnancy. The intensity of immunostaining for the betaA-subunit was strong during the menstrual phase, became weaker during the early proliferative phase, and was intense again at the late proliferative phase. The immunostaining for the betaA-subunit was weak during the early secretory phase and became very intense toward the midsecretory and late secretory phases. The intensity of immunostaining for activin A changed during the menstrual cycle and showed a tendency similar to that for betaA-subunit. The stromal cells were weakly immunoreactive with antibodies against the betaA-subunit and activin A from the menstrual to the midsecretory phase and became strong in the late secretory phase. Intense staining for the betaA-subunit and activin A was observed in the cytoplasm of decidual cells during early pregnancy.


CONCLUSIONS
Activin A, but not inhibins, is localized in the endometrial tissue. The endometrium may be a major source of activin A during the normal menstrual cycle, and the decidua may be one of the sources of activin A during early pregnancy.
Otani
T
T
Department of Obstetrics and Gynecology, Wakayama Medical College, Shichibancho, Japan.
Minami
S
S
Kokawa
K
K
Shikone
T
T
Yamoto
M
M
Nakano
R
R
D028341:Activins; D000328:Adult; D004717:Endometrium / Q000737:chemistry*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000037:antagonists & inhibitors; D006801:Humans; D007150:Immunohistochemistry; D007265:Inhibins / Q000032:analysis*; D008597:Menstrual Cycle / Q000378:metabolism*; D008875:Middle Aged; D011247:Pregnancy / Q000378:metabolism*; D011261:Pregnancy Trimester, First
D028341:Activins; D007265:Inhibins; D005640:Follicle Stimulating Hormone