Growth hormone and insulin-like growth factor-I action on XXXX secretion by porcine corpora lutea isolated at various periods of the luteal phase.

@entity1707 @entity1420 @entity1880 @entity1816 @entity3333 @entity4316 @entity10850
This study was conducted to investigate the interactions between growth hormone (GH) and insulin-like growth factor-I ( @entity10850 ) on @entity1420 (P4) secretion by porcine luteal cells cultured in vitro. Cells isolated from corpora lutea (CL) collected at three different periods of the luteal phase (CL1--early luteal phase; CL2--middle luteal phase and CL3--late luteal phase) were incubated with different doses of GH (10, 100 or 200 ng/ml). After 48 h cultures were terminated and the media were frozen until further P4 concentration analysis. GH (100 ng/ml) increased P4 secretion by CL1 and CL2 and had no effect on CL3. In separate studies these cells were treated for 48 h with @entity10850 alone or with GH combined with @entity10850 . @entity10850 alone increased basal P4 secretion only by cells collected from CL1 while concurrent treatment with GH had no effect on P4 secretion by any type of CL. To investigate the possible mechanism of GH and @entity10850 mediated induction of P4 secretion, an inhibitory study was conducted. In this experiment, luteal cells collected from CL1 were cultured in the absence or presence of @entity1880 (an inhibitor of protein synthesis) or @entity4316 (an inhibitor of DNA transcription). @entity1880 or @entity4316 completely blocked the stimulatory effect of both GH and @entity10850 on P4 production but did not reduce basal @entity1420 secretion suggesting involvement of gene transcription and translation in the GH and @entity10850 action on luteal cells. Additionally, the activity of @entity1816 dehydrogenase (3 beta-HSD) under the influence of GH added alone or together with IGF was measured by the conversion of @entity3333 to @entity1420 . Stimulation of P4 secretion in P5-treated cells in GH-stimulated cultures was not observed, however, high stimulatory effect was noted in @entity10850 treated cultures. In conclusion, the present studies indicate that there is direct and cycle stage dependent influence of GH and @entity10850 on steroidogenesis in procine luteal cells. It is suggested that both IGF and GH may exert some regulatory action during CL development in the @entity1707 .
