Regulation of testicular differentiation and testosterone production in the fetal mouse gonad in vitro.
The objective of the present study was to develop a chemically-defined medium in which early stages of testicular differentiation can be investigated in an organ culture system. Mouse gonadal primordia were explanted before and after initiation of morphological sex differentiation, i.e. 11 and 12 day of gestation (d.g.), respectively. We found that a combination of human albumin fraction, insulin (or IGF-I), and sodium pyruvate promoted testicular organization of gonadal explants of 11 d.g., but not those of 12 d.g. Insulin also increased the production of testosterone from testicular explants of 11 d.g., but not those of 12 d.g. For the younger explants, progesterone was more efficient than pregnenolone as a steroid precursor during the first day of culture, but the maximum effect of pregnenolone was much higher than that of progesterone in later stages. The responsiveness to human chorionic gonadotropin increased gradually along with testicular organization. The addition of either serum or pregnenolone prominently increased the activity of delta 5-3 beta hydroxysteroid dehydrogenase in testicular explants of 11 d.g., but not the number of positive cells as demonstrated by histochemical staining. These results suggest that insulin (or IGF-I) is required during the initial phase of testicular organization, which is reflected by an increase in testosterone production and sensitivity to gonadotropins.
Taketo
T
T
McGill University, Royal Victoria Hospital, Montreal, Canada.
Saeed
J
J
Roberge
S
S
Matsuo
N
N
Koide
S S
SS
D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D000418:Albumins / Q000494:pharmacology; D000818:Animals; D002454:Cell Differentiation; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D006651:Histocytochemistry; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D008297:Male; D051379:Mice; D009924:Organ Culture Techniques; D011284:Pregnenolone / Q000494:pharmacology; D011374:Progesterone / Q000494:pharmacology; D011773:Pyruvates / Q000494:pharmacology; D019289:Pyruvic Acid; D013737:Testis / Q000166:cytology* / Q000196:embryology / Q000378:metabolism; D013739:Testosterone / Q000096:biosynthesis*
D000418:Albumins; D006063:Chorionic Gonadotropin; D007328:Insulin; D011773:Pyruvates; D013739:Testosterone; D011374:Progesterone; D011284:Pregnenolone; D019289:Pyruvic Acid; D015096:3-Hydroxysteroid Dehydrogenases