This study examines the possibility of a feedback interaction between gonadal relaxin and the pituitary by investigating the impact of exogenous relaxin and ablation of endogenous with relaxin anti-relaxin serum on pituitary hormone secretion in vitro. Three wells were assigned to treatments: 0, 100 and 1000 ng ml-1 of relaxin, 1:100, 1:1000 and 1:10000 titer of anti-relaxin. Relaxin significantly enhanced prolactin (PRL) secretion (P < 0.05) in long-term culture but had no effect on luteinizing hormone and follicle stimulating hormone secretion. Relaxin anti-serum stimulated a dose dependent increase (P < 0.05) in gonadotropin secretion at 48, 72 and 96 h. Luteinizing hormone and follicle stimulating hormone increased two-fold in 48 h cultures in response to 1:100 anti-relaxin serum in comparison with untreated controls. Anti-relaxin serum at 1:100 completely suppressed PRL secretion after either 48, 72, and 96 h of culture. At 48 h all levels of anti-relaxin serum completely suppressed PRL secretion. These results indicate that endogenous relaxin may be involved at the adenohypophysial level in modulating gonadotropin and PRL release in the pig.
Bibliographical noteFunding Information:
This project was funded by a St. Cloud State University Faculty Research Grant 1993/94. Technical support was provided by S.L. Baker. Visual aids technical support was provided by Mary Craighton Shrode of SCSU. The relaxin and anti-relaxin serum used in this study was provided by Dr. C. Schwabe, Department of Biochemistry and Molecular Biology, Medical University of South Carolina.
- Adenohypophysial cells
- Luteal function