Gonadotropin binding sites in human postmenopausal ovaries.

Area of Science:

• Endocrinology
• Reproductive Biology
• Histochemistry

Background:

• Postmenopausal ovaries undergo significant structural and functional changes.
• The role of residual ovarian cells in hormone production after menopause is not fully understood.
• Gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), are key regulators of ovarian function.

Purpose of the Study:

• To investigate the presence and localization of Glucose-6-phosphate dehydrogenase (G6PD) activity in postmenopausal ovaries.
• To identify and localize gonadotropin binding sites within postmenopausal ovarian tissues.
• To determine if postmenopausal ovarian cells retain the capacity for gonadotropin-mediated steroidogenesis.

Main Methods:

• Histochemical staining for G6PD activity using Nitro-Blue tetrazolium.
• Autoradiography to detect binding sites for iodinated human luteinizing hormone (125I-hLH) and follicle-stimulating hormone (125I-hFSH).
• Examination of ovarian sections from seven postmenopausal women.

Main Results:

• G6PD activity was detected in the cortical stroma and hilus cells of postmenopausal ovaries.
• Gonadotropin binding sites for both hLH and hFSH were identified in the same cellular locations (cortical stroma and hilus cells).
• Blood vessels also exhibited gonadotropin binding, with FSH binding often being more intense than LH binding.

Conclusions:

• Postmenopausal ovarian stromal and hilus cells possess G6PD activity and receptors for both LH and FSH.
• These findings indicate that steroidogenesis in postmenopausal ovaries may be regulated by circulating gonadotropins.
• The presence of these components suggests a potential for residual endocrine function in the postmenopausal ovary.