Role of IGFs and insulin in the human testis during postnatal activation: differentiation of steroidogenic cells.
Immunoexpression of IGF-I, IGF-II, type 1 IGF receptor (IGFR), insulin receptor (IR), and GH receptor (GHR) was analyzed in human testis, in three age groups (Gr): Gr1 (neonates), Gr2 (postnatal testicular activation), and Gr3 (early prepuberty). In interstitial cells, low IGF-I and GHR, but moderate IR immunoexpression was observed in all Grs. However, high expression of IGF-II in Gr1, and moderate expression of IGFR in Gr1 and Gr2 were found. In Leydig cell (LC), high expression of IGF-II, moderate expression of IGFR and GHR, and undetectable IGF-I was found. Moreover, IR was highly expressed in Gr2. The effect of IGF-I on cell proliferation (PI) and apoptosis (AI), induction of cytochrome P450 side chain cleavage (cP450scc) immunoexpression, 3beta-hydroxysteroid dehydrogenase mRNA and testosterone (T) secretion was evaluated in human testis cell cultures. IGF-I increased P450scc immunoexpression, 3beta-hydroxysteroid dehydrogenase mRNA, T secretion, and PI, but decreased AI. We propose that IGF-II, mainly through IR, is involved in functional LC differentiation. In some interstitial cells, probably in LC precursors, IGF-II/IR could be involved, among other factors, in the stimulation of PI and/or inhibition of AI, and in LC differentiation.
Endocrine Service, Hospital de Pediatria Garrahan, Buenos Aires C1245 AAM, Argentina.
Esperanza B
EB
Berensztein
María S
MS
Baquedano
Carolina M
CM
Pepe
Mariana
M
Costanzo
Nora I
NI
Saraco
Roberto
R
Ponzio
Marco A
MA
Rivarola
Alicia
A
Belgorosky
D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics / Q000378:metabolism; D000367:Age Factors; D017209:Apoptosis; D001344:Autopsy; D002352:Carrier Proteins / Q000378:metabolism; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D002675:Child, Preschool; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000378:metabolism; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007328:Insulin / Q000378:metabolism*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D007335:Insulin-Like Growth Factor II / Q000378:metabolism*; D007985:Leydig Cells / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D011972:Receptor, Insulin / Q000378:metabolism; D017451:Receptors, Somatomedin / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction; D013737:Testis / Q000166:cytology / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism
D002352:Carrier Proteins; D007328:Insulin; D012333:RNA, Messenger; D017451:Receptors, Somatomedin; D011994:Recombinant Proteins; D013739:Testosterone; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D015096:3-Hydroxysteroid Dehydrogenases; D002786:Cholesterol Side-Chain Cleavage Enzyme; D011972:Receptor, Insulin; C051815:somatotropin-binding protein