Meunier, H., Rivier, C., Evans, R. M., & Vale, W. (1988). Gonadal and extragonadal expression of inhibin alpha, beta A, and beta B subunits in various tissues predicts diverse functions. Proceedings of the National Academy of Sciences of the United States of America, 85(1), 247-251. https://doi.org/10.1073/pnas.85.1.247
Meunier H, Rivier C, Evans RM, Vale W. Gonadal and extragonadal expression of inhibin alpha, beta A, and beta B subunits in various tissues predicts diverse functions. Proc Natl Acad Sci U S A. 1988;85(1):247-251. doi:10.1073/pnas.85.1.247
Meunier, H., et al. "Gonadal and extragonadal expression of inhibin alpha, beta A, and beta B subunits in various tissues predicts diverse functions." Proceedings of the National Academy of Sciences of the United States of America, vol. 85, no. 1, 1988, pp. 247-251.
Rat brain, placenta and bone marrow also make inhibin RNA
Rat brain, placenta, and bone marrow carry inhibin subunit RNA, a laboratory study of male and female rats found, along with the ovary and testis. Young rat testes carried more of it than mature testes. The authors propose that inhibin dimers may act as growth and differentiation factors as well as a hormone.
Key Findings
Inhibin subunit RNAs appeared outside the ovary and testis, including the brain, spinal cord, placenta, pituitary, adrenal, kidney, and bone marrow, with different subunits in different tissues.
In the placenta, beta A RNA was 6- to 10-fold more abundant than alpha and beta B RNAs. Bone marrow showed significant beta A RNA, while alpha and beta B stayed undetectable.
In the mature ovary, beta A and beta B RNAs were less abundant than alpha RNA by a factor of 6-10. In the mature testis, they were 50 and 15 times lower.
Testicular RNA for all three subunits was 4- to 10-fold higher in rats aged 8 to 15 days than in rats aged 90 days. Beta A RNA declined most rapidly.
Interpretation
This is a laboratory study in Sprague-Dawley rats. The method measures RNA, the message copied from a gene before a protein is made. The study did not measure protein levels or actions, and the authors offer their functional ideas as proposals to investigate. Each tissue came from animals of one sex. The authors write that it remains to be established whether the relative amount of each RNA indicates which inhibin dimer a tissue makes.
RRM Context
Inhibin is a hormone from the ovary and testis. It feeds back on the pituitary gland to restrain follicle-stimulating hormone (FSH), the pituitary signal to both gonads. Restorative reproductive medicine treats the reproductive hormone system as connected to the whole body. Basic findings like these add detail, including roles the authors propose for inhibin in the placenta, bone marrow, and nervous system.
Our editorial summary of this paper, not the article's abstract.
Abstract
The S1-nuclease analysis was used to investigate the pattern of inhibin expression in the rat. In a first series of experiments, expression of the alpha, beta A, and beta B subunits of inhibin were monitored in various tissues from male and female rats. Two observations emerge from these studies. First, expression of inhibin subunits was found in gonadal and extragonadal tissues. In addition to the ovary and testis, inhibin alpha, beta A, and beta B RNAs were detected in the placenta, pituitary, adrenal, bone marrow, kidney, spinal cord, and brain. Detection of inhibin RNAs in the brain and spinal cord suggested that these subunits may exert neuroregulatory functions in the central and peripheral nervous systems. Furthermore, the presence of inhibin alpha and beta subunits in the placenta and the pituitary gland, two cell types that have clearly been shown to be regulated by exogenous inhibin, may reflect existing paracrine and/or autocrine processes active in these tissues. The second observation is that expression of inhibin subunit RNAs may vary by severalfold in a tissue-specific fashion. for example, alpha-subunit RNA levels are abundant in the gonads, whereas beta A-subunit RNA is predominant in the placenta and bone marrow. Finally, it is noted that expression of testicular inhibin RNA subunits decreases during sexual maturation. We conclude that the dimers comprised of inhibin subunits possess diverse functions and may act as growth/differentiation factors as well as a hormone.
PMID 2829170 2829170 DOI 10.1073/pnas.85.1.247 10.1073/pnas.85.1.247 Meunier et al. 1988, Meunier 1988
Keywords
Animals, DNA/genetics/isolation & Purification, Endonucleases, Female, Inhibins/genetics, Macromolecular Substances, Male, Organ Specificity, Ovary/metabolism, Rats, Rats, Inbred Strains, Single-Strand Specific DNA and RNA Endonucleases, Testis/metabolism, Macromolecular Substances, Inhibins, DNA, Endonucleases, Single-Strand Specific DNA and RNA Endonucleases
