Paracrine effect of seminiferous tubule factors on rat Leydig cell testosterone production: role of cytoskeleton.
In Percoll purified Leydig cells from mature rat we have demonstrated that the basal testosterone production (9.5 ng/10(6) Leydig cells/24 h) is increased 10-fold in presence of a saturating amount of hCG (1 IU/mL) and diminished in a dose-related manner when larger concentrations of gonadotropin are used to reach 14 ng/10(6) Leydig cells for 50 IU of hCG. If 40% (v/v) seminiferous tubule medium (STM) is added together with hCG (1 IU/mL) to the incubation medium, a further increase (62%) of testosterone output is noticed. Obviously, when the testosterone production is low as a consequence of a higher dose of hCG (50 IU/mL), the STM (80%) improves the steroid synthesis five-fold (67.4 ng). Concerning the cytoskeletal components (microtubules, intermediate filaments and microfilaments) which have been examined in presence or absence of hCG and STM, we have found a rearrangement of cytoskeletal elements as well as cell-shape changes in relation with hormonal activity of the cells. The most prominent alterations of cytoskeletal elements have been observed after 24 h of incubation with 1 IU/mL of hCG added together with 80% of STM. The obtained results suggest that paracrine factor(s) presents in STM and acting in synergy with LH/hCG generate(s) the rearrangement of cytoskeletal structures which, in turn, facilitates the availability of cholesterol for the mitochondria and finally enhances the testosterone production in the rat Leydig cells.
Bilinska
B
B
Laboratoire de Biochimie-IRBA, EP CNRS 009, Université de Caen, France.
Genissel
C
C
Carreau
S
S
D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D003599:Cytoskeleton / Q000502:physiology* / Q000648:ultrastructure; D007150:Immunohistochemistry; D007985:Leydig Cells / Q000378:metabolism* / Q000648:ultrastructure*; D008297:Male; D019899:Paracrine Communication; D051381:Rats; D012671:Seminiferous Tubules / Q000378:metabolism*; D013739:Testosterone / Q000096:biosynthesis*
D006063:Chorionic Gonadotropin; D013739:Testosterone