Identification, ontogeny, and regulation of an interleukin-6-like factor in the rat seminiferous tubule.
The present study's aims are to search for the presence of interleukin-6 bioactivity (IL-6) in medium conditioned by various testicular cell types and to investigate the cellular and hormonal regulation of testicular IL-6 production. Sertoli cells prepared from rats of increasing ages (20, 35, and 45 days) secreted IL-6 in vitro, whereas medium conditioned by pachytene spermatocytes, early spermatids, and peritubular cells showed no activity. Lipopolysaccharide (LPS) and latex beads, two known stimulators of monocyte/macrophage IL-6 production, markedly stimulated IL-6 secretion by Sertoli cells at all the ages investigated. Maximum levels of IL-6 were reached after 6 h of culture of Sertoli cells with LPS and after 24 h with latex beads. When Sertoli cells were cocultured with pachytene spermatocytes, early spermatids, or fractions containing residual bodies and cytoplasts from elongated spermatids, only the latter significantly stimulated IL-6 levels. Maximum levels of IL-6 were attained by adding 2 x 10(6) residual bodies to Sertoli cells; a significant increase in IL-6 secretion was seen after 6 h, and maximum levels were observed after 24 h. The levels of IL-6 varied throughout different stages of the seminiferous epithelium cycle; highest levels were observed in stages II-VI and lowest in stages VII-VIII. IL-6 bioactivities induced by LPS and residual bodies and cytoplasts from elongated spermatids could be totally neutralized with a specific monoclonal antibody at all of the ages studied. FSH, phorbol myristate acetate, and IL-1 alpha augmented Sertoli cell IL-6 secretion in a dose-dependent manner. Furthermore, FSH and (Bu)2cAMP differentially stimulated IL-6 secretion during the seminiferous epithelial cycle. It is concluded that the release of IL-6 from Sertoli cells is regulated by a complex interplay between residual bodies and humoral factors.
GERM, INSERM CJF 91-04, Université de Rennes 1, Bretagne, France.
V
V
Syed
N
N
Gérard
A
A
Kaipia
C W
CW
Bardin
M
M
Parvinen
B
B
Jégou
D000375:Aging / Q000378:metabolism; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002478:Cells, Cultured; D005640:Follicle Stimulating Hormone / Q000494:pharmacology; D015850:Interleukin-6 / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D008863:Microspheres; D051381:Rats; D017207:Rats, Sprague-Dawley; D012670:Seminiferous Epithelium / Q000502:physiology; D012671:Seminiferous Tubules / Q000254:growth & development* / Q000378:metabolism; D012708:Sertoli Cells / Q000378:metabolism*; D013087:Spermatids / Q000378:metabolism; D013094:Spermatozoa / Q000378:metabolism
D015850:Interleukin-6; D008070:Lipopolysaccharides; D003994:Bucladesine; D005640:Follicle Stimulating Hormone