In vitro biosynthesis of steroids in ovary of asynchronic Trichogaster trichopterus (Pallus, 1770)

Abstract The relationship between ovarian steroidogenesis and the development of oogenesis was studied in the ovary of Trichogaster trichopterus by histological examination and thin layer chromotography. The percent yield of 17β-estradiol (E 2 ) was high at a number of different stages of vitellogenesis, while those of 17α,20β-dihydroxy-4-pregnen-3-one (17,20-P) and testosterone (T) were high at the beginning of maturation, and increased steadily during this process. The per cent yields of T and 17α-hydroxyprogesterone (17-P) were low at all stages of vitellogenesis (VTG). For androstenedione (AS), 5-androstane-3β-ol-17-one, 5β-pregnane-3α,17α,20α-triol and 11-ketotestosterone, the per cent yields appeared to increase mainly during maturation and ovulation. It is suggested that the main pathways of steroidogenesis during oogenesis are: at VTG, [P]→[17-P]→[AS]→[E 2 ]; and at maturation [17-P] → [17,20-P], the latter controlled by male stimulation of GtH.