In-vitro modulation of plasminogen activator activity, prostaglandin E and nitric oxide production by interleukin-1 in pregnant mare serum gonadotrophin-primed theca-interstitial cells

Transforming growth factor-beta isoform expression during bovine ovarian antral follicle development

Transforming growth factor-beta (TGF-beta) isoforms are important paracrine and autocrine signaling molecules for the regulation of ovarian follicle growth and physiology. Effective communication between the epithelial granulosa cells, the mesenchymal theca cells, and the oocyte is vital for ovarian function and reproductive success. The expression, localization, and regulation of TGF-beta isoforms in the developing bovine follicle was examined using both immunohistochemistry and quantitative reverse transcription-polymerase chain reaction (RT-PCR) procedures. TGF-beta1 protein was found to be present in the granulosa cells of early pre-antral, early antral, and 1-2 mm follicles. Interestingly, there was no visible staining of granulosa cells of 3-5 or 5-10 mm follicles. There was also no TGF-beta1 staining of theca cells. TGF-beta2 and TGF-beta3 staining were present in the granulosa and theca cells of all follicle stages examined. The levels of TGF-beta mRNA expression in granulosa and theca cells from antral follicles was measured using quantitative RT-PCR. For each isoform mRNA expression levels did not change in different sized antral follicles. TGF-beta3 mRNA levels were much higher than those of TGF-beta1 and TGF-beta2 in both granulosa and theca. Expression levels were higher in theca than in granulosa for TGF-beta2 and TGF-beta3. FSH was found to decrease TGF-beta1 mRNA expression in granulosa cells, but had no effect on TGF-beta2 and TGF-beta3. Bovine ovarian follicles were found to have a unique pattern of TGF-beta isoform expression and regulation when compared to other species (i.e., rodent, pig, quail, and human). The similarities and differences between the various species is discussed to help elucidate common functions of TGF-beta in the ovary. In summary, observations demonstrate that as antral follicles develop, TGF-beta3 is the most abundant TGF-beta isoform and TGF-beta1 protein levels decline in large follicles. Granulosa cell TGF-beta1 expression was decreased by FSH and this correlated with reduced levels in large antral follicles. TGF-betas involved in antral follicular growth and development appear to act as paracrine/autocrine signaling molecules having a species-specific pattern of expression.

Interleukin-1 beta inhibits progesterone accumulation in rat corpora luteal cell cultures in a mechanism dissociated from its effects on nitric oxide and prostaglandin E accumulation

The objective of this study was to examine the effect of interleukin-1 beta (IL-1) on progesterone (P) biosynthesis and the potential intermediary involvement of prostaglandin (PG) E and nitric oxide (NO) in P accumulation in PMSG/hCG-primed rat corpora luteal (CL) cell cultures. Exposure of primed CL cells to IL-1 (10 ng/ml) for 48 h resulted in a 65-86% reduction (P < 0.01) in P accumulation concurrent with a 2-3.4-fold increase in PGE content, a 70% increase in PGF2 alpha content and a 1.9-3.3-fold increase in nitrite generation. These effects were abolished by the IL-1 receptor antagonist, suggesting specific IL-1 receptor-mediated effects. Indomethacin, a cyclooxygenase inhibitor, abolished PGE and PGF2 alpha production and attenuated the basal (but not IL-1-stimulated) accumulation of P. N(G)-Nitro-L-arginine (NNLA), a competitive inhibitor of nitrite synthesis, slightly reduced basal P accumulation but had no effect on IL-1-induced suppression of P accumulation. NNLA reduced basal PGE accumulation and IL-1-stimulated PGE accumulation (55 and 61%, respectively). Transforming growth factor beta 1 (TGF-beta 1; 10 ng/ml) significantly attenuated the IL-1-stimulated PGE and NO production (61 and 42%, respectively), but did not affect the ability of IL-1 to suppress P accumulation. Thus, NO, PGF2 alpha and PGE are not obligatory intermediaries of IL-1-mediated suppression of P accumulation in rat CL, but are involved in basal P biosynthesis and NO seems to have a regulatory role in the biosynthesis of PGE. The present observations suggest a pleiotropic response of PMSG/hCG-primed CL cells to IL-1, characterized by an independent suppression of P accumulation and a concomitant increase in NO, PGF2 alpha and PGE generation. Since IL-1 attenuates P accumulation, these findings may imply a direct autocrine/paracrine function for IL-1 in the maintenance or the demise of rat CL.