Differentiation of adult-type Leydig cells occurs in gonadotrophin-deficient mice.
During mammalian testis development distinct generations of fetal and adult Leydig cells arise. Luteinising hormone (LH) is required for normal adult Leydig cell function and for the establishment of normal adult Leydig cell number but its role in the process of adult Leydig cell differentiation has remained uncertain. In this study we have examined adult Leydig cell differentiation in gonadotrophin-releasing hormone (GnRH)-null mice which are deficient in circulating gonadotrophins. Adult Leydig cell differentiation was assessed by measuring expression of mRNA species encoding four specific markers of adult Leydig cell differentiation in the mouse. Each of these markers (3beta-hydroxysteroid dehydrogenase type VI (3betaHSD VI), 17beta-hydroxysteroid dehydrogenase type III (17betaHSD III), prostaglandin D (PGD)-synthetase and oestrogen sulphotransferase (EST)) is expressed only in the adult Leydig cell lineage in the normal adult animal. Real-time PCR studies showed that all four markers are expressed in adult GnRH-null mice. Localisation of 3betaHSD VI and PGD-synthetase expression by in situ hybridisation confirmed that these genes are expressed in the interstitial tissue of the GnRH-null mouse. Treatment of animals with human chorionic gonadotrophin increased expression of 3betaHSD VI and 17betaHSD III within 12 hours further indicating that differentiated, but unstimulated cells already exist in the GnRH-null mouse. Thus, while previous studies have shown that LH is required for adult Leydig cell proliferation and activity, results from the present study show that adult Leydig cell differentiation will take place in animals deficient in LH.
Baker
P J
PJ
Institute of Comparative Medicine, University of Glasgow, Veterinary School, Bearsden Rd, Glasgow G61 1QH, UK. p.j.baker@vet.gla.ac.uk
Johnston
H
H
Abel
M
M
Charlton
H M
HM
O'Shaughnessy
P J
PJ
D015067:17-Hydroxysteroid Dehydrogenases / Q000096:biosynthesis / Q000235:genetics; D015096:3-Hydroxysteroid Dehydrogenases / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D007987:Gonadotropin-Releasing Hormone / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D019746:Intramolecular Oxidoreductases / Q000096:biosynthesis / Q000235:genetics; D007985:Leydig Cells / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D054834:Lipocalins; D007986:Luteinizing Hormone / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000494:pharmacology; D015238:Sulfotransferases / Q000096:biosynthesis / Q000235:genetics
D006063:Chorionic Gonadotropin; D054834:Lipocalins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D015067:17-Hydroxysteroid Dehydrogenases; C476565:17beta-hydroxysteroid dehydrogenase type 3; D015096:3-Hydroxysteroid Dehydrogenases; D015238:Sulfotransferases; C020122:estrone sulfotransferase; D019746:Intramolecular Oxidoreductases; C022466:prostaglandin R2 D-isomerase