Response of porcine theca and granulosa cells to GH during short-term in vitro culture

In Experiment 1, the influence of exogenous GH on steroid secretion by gran ulosa and theca interna cells recovered from small (1-3 mm), medium (4-6 mm ) and large (8-12 mm) follicles was tested. In the second experiment, theca cells (Tc) and granulosa cells (Gc) obtained from large follicles were cul tured separately or in two types, Tc/Gc co-culture, where both types of cel ls were mixed in one well or Gc and Tc were separated by cell culture membr ane inserts. In the third experiment, the influence of GH on the morphology of Ge and Tc cells and activity of Delta(5),3 beta-hydroxysteroid dehydrog enase (3 beta-HSD) was studied. Cells were grown in the control medium (M19 9 + 5% of calf serum) or supplemented with 100 ng/ml GH. Testosterone (10(- 7) M) was added as the aromatase substrate to granulosa cells cultures. The media were assayed after 48 h of culture for progesterone and oestradiol b y RIA. GH added to the culture media had no effect on oestradiol and proges terone secretion by granulosa cells isolated from small and medium follicle s while it stimulated both oestradiol and progesterone secretion by Gc isol ated from large preovulatory follicles, A stimulatory effect on oestradiol secretion by Tc isolated from all size follicles was observed. GH did not s timulate progesterone secretion by Tc isolated from small follicles bur sti mulated progesterone secretion by Tc isolated from medium and large preovul atory follicles, Both co-culture systems exhibited synergistic effect on oe stradiol secretion. The stimulatory effect on progesterone secretion under the influence of GH was observed in Gc cultured alone and Tc cultured alone . In contrast, the secretion of progesterone was attenuated in both co-cult ure systems and the addition of GH further augmented this attenuation. A st atistically significant increase in oestradiol secretion was observed in al l culture conditions. The addition of GH to the culture medium stimulated t he activity of 3 beta-HSD compared with the control culture from both types of cells. In conclusion, the present studies indicate that there are direc t and follicular development stage dependent actions of GH on steroidogenes is or porcine follicular cells. (C) 2000 Elsevier Science B.V. All rights r eserved.