POPLINE Document Number: 075756
Author(s):
Benahmed M
Sordoillet C
Hartmann DJ
Esposito G
Cochet C
Tabone E
de Peretti E
Chauvin MA
Morera AM
Source citation:
In: Growth factors in fertility regulation. Proceedings of the Symposium on Potential of Molecular Biology in Fertility Regulation: Growth Regulatory Factors, jointly sponsored by the World Health Organization and the National Institute of Child Health and Human Development and held at the National Institutes of Health, Bethesda, Maryland, on September 22-24, 1988, edited by Florence P. Haseltine, Jock K. Findlay. Cambridge, England, Cambridge University Press, 1991. :235-59. (Scientific Basis of Fertility Regulation)
Abstract:
The research reported proposes that transforming growth factor-beta (TGF-beta) and its related peptides represent a family of polypeptides involved in local intercellular communication within the testis. Populations of purified cell types, Leydig, peritubular myoid, and Sertoli cells, from the 3-week old hog testis were incubated in defined media. TGF has the characteristics of a local regulator: it is known to be a potent regulator of cell proliferation of epithelial, adipose, osteocyte, steroidogenetic, and fibrous matrix-producing cells. It occurs in a family of hetero-dimers as well as latent forms, and binds to cell surfaces with high affinity. TGF is related to inhibins, activins, and Mullerian inhibiting substances. Sertoli cells produce TGF-beta, a process inhibited by follicle stimulating hormone (FSH) and enhanced by estradiol, glucocorticoids, and thyroxine. TGF-beta mRNA was also detected in Leydig and peritubular myoid cells of the testis. TGF-beta causes Leydig cells to elongate during incubation, and to lose the ability to bind LH, by down-regulating numbers of receptors. TGF-beta stimulated testosterone production at low concentrations up to 0.1 ng/ml, and inhibited testosterone release at concentrations over 1 ng/ml, a process not affected by cyclic AMP. This effect could be broken down into a biphasic stimulation of 3beta hydroxysteroid dehydrogenase, and inhibition of pregnenolone formation in the testosterone pathway. Preliminary experiments showed that TGF-beta is involved in formation of extracellular matrix, a Sertoli cell androgenic inhibiting factor, and FSH stimulation of lactate production. The authors propose a comprehensive model of intercellular communication in the developing testis involving gonadotropins, other steroid and thyroid hormones, and other growth factors.
Keywords:
Research ReportIndex page
Literature Review
Clinical Research
Physiology
Cytology
Adenosine Cyclic Monophosphate
Androgens
Testosterone
Dehydroepiandrosterone
Corpus Luteum Hormones
Adrenal Cortex Hormones
Follicle Stimulating Hormone
Luteinizing Hormone
Enzymes
Hormone Receptors
Testis
Animals, Laboratory
In Vitro
Research Methodology
Biology
Hormones
Endocrine System
Gonadotropins, Pituitary
Gonadotropins
Enzymes and Enzyme Inhibitors
Membrane Proteins
Genitalia, Male
Genitalia
Urogenital System