Effect Of An Extract Of Superior Ovarian Nerve On Steroidogenesis By Porcine Theca Cells In Vitro

Publication Year:
1990
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Downloads 73
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Repository URL:
https://ir.lib.uwo.ca/digitizedtheses/1894
Author(s):
Morley, Paul Andrew
Tags:
Biology; Animal Physiology
thesis / dissertation description
Ovarian steroidogenesis may be controlled not only by pituitary gonadotropins, but also by ovarian nerves. Nerves reach the ovary via the plexus nerve and the superior ovarian nerve (SON), and innervate the theca cells of all follicles. Thecal androgen biosynthesis is primarily controlled by luteinizing hormone (LH); however, the presence of nerves close to these cells has raised the question of whether nerves can modulate their androgen biosynthesis. The purpose of this study was to develop a porcine theca cell culture system, and to use it to investigate the effects of putative ovarian neurotransmitters and ovarian nerve factors on thecal steroidogenesis. Theca cells from prepubertal gilts cultured under serum-free conditions responded to LH with increased cyclic AMP and androstenedione accumulation. Catecholamines, acting via {dollar}\beta{dollar}-adrenergic receptors, caused a generalized inhibition of thecal steroidogenesis at a site distal to the generation of cyclic AMP. The direct effects of ovarian nerve factors on thecal steroidogenesis were studied by adding extracts of rat SON to cultured theca cells. Addition of SON extract inhibited androstenedione accumulation. The inhibitory activity of the SON extract was unaffected by chymotrypsin treatment or boiling, but was removed by charcoal treatment. The extract contained immunoreactive estradiol which, in common with the inhibitory activity, was extractable with organic solvents and eluted in the same fractions on Sephadex LH-20 columns. Estradiol, catecholestrogens and the SON extract inhibited the 17{dollar}\alpha{dollar}-hydroxylase:C{dollar}\sb{lcub}17-20{rcub}{dollar} lyase enzyme complex. The results suggest that the SON contains a factor which inhibits thecal androstenedione production and a factor which cross reacts with an estradiol antibody. It is not known if these factors are the same or distinct compounds. Therefore, the nervous system may have the potential to modulate follicular steroid biosynthesis via a direct innervation of the ovaries. Ovarian nerves may play important roles in the regulation of follicular development, since thecal androgens are substrates for estradiol biosynthesis and are involved in follicular atresia.