Progestin Production during Superfusion of Ovaries from Cycling Rats

Abstract

Superfusion of partially sliced ovarian tissue from cycling rats using a continuous flow of buffered saline was found to be a useful method for in vitro experimentation. The major metabolite of 3 H-progesterone (P) formed by superfused tissue was 20a-dihydroprogesterone (20aOH-P). Tissue from rats at all stages of the estrous cycle released detectable amounts of both P and 20aOH-P, with the latter steroid predominating. The 20aOH-P/P ratio was highest with proestrus and estrus tissue. The progestins were produced at a constant basal rate during superfusion for at least 24 hr. The greatest amounts of both steroids were released by diestrus tissue. Pulses of human chorionic gonadotropin administered to estrus and diestrus I tissue during superfusion were followed by increases in the amounts of steroids in the superfusate. Smaller and more variable effects were seen with proestrus and diestrus II tissue. The results obtained both before and after gonadotropic stimulation were consistent with production of the progestins primarily by the cells of the corpora lutea. {Endocrinology 92: 265, 1973)

Patterns of growth, oestradiol and progesterone released by in vitro cultured mouse ovarian follicles indicate consecutive selective events during follicle development

“…In consequence, progesterone secretion could not be associated with luteinization and must be considered as a normal attribute of mouse follicles. This suggestion is sup¬ ported by a report that in vitro superfused slices of rat ovarian tissue released detectable amounts of progestins at all stages of the oestrous cycle (Anderson et al, 1973). However, the reported increase in progestin secretion and associated decrease in oestrogen release by clumps of follicles towards the end of a much longer culture period of mouse ovarian follicles (Qvist et al, 1990) is strongly suggestive of luteinization.…”

Superfusion in Vitro in the Study of Ovarian Steroidogenesis

“…The considerable variation in response to gonadotrophin between experiments gave some cause for concern, and was also noted by Anderson et al (1973) in their studies with superfused rat ovaries. A possible explanation for this variation in the present system has been obtained in recent experiments in which the binding of 125I-labelled-LH to porcine luteal tissue was studied under identical superfusion conditions (Leask, Watson & Anderson, 1974).…”

“…Preliminary results of these studies have already been reported Watson, Leask, Alam & Adams, 1973), and during the course of this work the technique has also been applied to the study of ovarian steroidogenesis in cyclic rats (Anderson, Turnipseed & Ungar, 1973).…”

“…Anderson et al (1973), in experiments in which steroid secretion from superfused rat ovaries was stimulated by human chorionic gonadotrophin (HCG), also noted a transient increase in secretion, in some experiments, with the main stimulation occurring some 60-90 min after the addition of gonadotrophin. These workers, however, were collecting 30-min samples and could in most experiments have missed the initial transient rise.…”