Lysyl Oxidase Gene Expression and Enzyme Activity in the Rat Ovary: Regulation by Follicle-Stimulating Hormone, Androgen, and Transforming Growth Factor-β Superfamily Members in Vitro

Harlow, Christopher R.; Rae, Mick; Davidson, Lindsay; Trackman, Philip C.; Hillier, Stephen G.

Abstract

Lysyl oxidase (LOX) catalyzes the final enzymatic reaction required for cross-linking of collagen and elastin fibers and therefore has a crucial role in regulating the formation and maintenance of extracellular matrix in the ovary. LOX mRNA is abundantly expressed in rat granulosa cells. To examine how regulation of LOX in the ovary might influence follicular development, we studied LOX mRNA expression and enzyme activity in rat granulosa cells from late preantral/early antral follicles in vitro. FSH dose dependently inhibited LOX mRNA and enzyme activity (50% reduction at 10 ng/ml) in vitro, and FSH action was mimicked by 8-bromo-cAMP, suggesting FSH action via elevation of cAMP. Dihydrotestosterone alone enhanced LOX mRNA and enzyme activity, but potentiated the effect of FSH, causing a further reduction. TGFβ1 alone dose dependently enhanced LOX mRNA (5-fold increase at 10 ng/ml) and activity (1.5-fold increase). FSH dose dependently inhibited the increase in LOX mRNA and activity caused by TGFβ1 (by up to 84% and 80%, respectively). Growth differentiation factor-9 (GDF-9) and activin A, at the same concentration as TGFβ1 (10 ng/ml), stimulated LOX mRNA and activity within 6 h, although overall expression was higher at 48 h. All three factors when combined with FSH further reduced both mRNA and enzyme activity (by up to 60%) compared with FSH alone. These findings indicate control of LOX at endocrine, paracrine, and autocrine levels within the ovary and suggest coordinated regulation of ovarian extracellular matrix during follicular development, with FSH determining whether local factors act as stimulators or inhibitors of LOX.

Citation

Harlow, C. R., Rae, M., Davidson, L., Trackman, P. C., & Hillier, S. G. (2003). Lysyl Oxidase Gene Expression and Enzyme Activity in the Rat Ovary: Regulation by Follicle-Stimulating Hormone, Androgen, and Transforming Growth Factor-β Superfamily Members in Vitro. Endocrinology, 144(1), 154-162. https://doi.org/10.1210/en.2002-220652

• Journal Article Type: Article
• Acceptance Date: Sep 13, 2002
• Publication Date: Jan 1, 2003
• Deposit Date: Jul 27, 2016
• Journal: Endocrinology
• Print ISSN: 0013-7227
• Electronic ISSN: 1945-7170
• Publisher: Endocrine Society
• Peer Reviewed: Peer Reviewed
• Volume: 144
• Issue: 1
• Pages: 154-162
• DOI: https://doi.org/10.1210/en.2002-220652
• Keywords: Endocrinology
• Public URL: http://researchrepository.napier.ac.uk/Output/317806