Abstract: 53

PROTEIN SYNTHESIS AND SECRETION BY PREANTRAL, EARLY ANTRAL, AND ANTRAL PORCINE FOLLICLES.

George Perry^{1 *}, Randall Prather^{1 *}, Kellie Alsup¹ , Leslie Falch¹ , Michael Smith^{1 *}
Department of Animal Science, University of Missouri-Columbia, Columbia, MO ¹

Follicular cells secrete a variety of proteins that have an important paracrine or autocrine role in regulating follicular and(or) oocyte function. Analysis of protein synthesis and secretion during the periods of antrum formation and greatest oocyte growth may provide insight into the development of culture systems that provide a larger source of oocytes capable of nuclear and cytoplasmic maturation. The objective was to characterize incorporation of ³⁵S-methionine (M) into proteins (cellular and secreted) and the rate of protein synthesis (M incorporation into protein/M uptake) by preantral (.15 to .25 mm), early antral (.35 to .65 mm), and antral (.75 to 6 mm) follicles. Ovaries were collected at an abattoir from prepuberal gilts and follicles were manually dissected and divided into the following groups according to follicular diameter: 1) .15 to .25 mm, 2) .35 to .45 mm, 3) .55 to .65 mm, 4) .75 to .85 mm, 5) 1 to 2 mm, and 6) 3 to 6 mm (3 replicates 4 follicles per size class). Follicles were cultured in M-deficient medium containing ³⁵S-M for 4h and evaluated for incorporation of radiolabel into cellular and secreted proteins and amino acid (M) uptake. Total DNA per follicle was determined on all six follicular size classes, and protein production was standardized by DNA. Cellular proteins (fmol M/µg DNA) increased from group 1 to 3 (p<0.05) and decreased (p<0.05) from group 3 to 6. Secreted proteins (fmol M/µg DNA) decreased (p<0.05) from group 1 to 2 to 3 to 5 and 6. While rate of protein synthesis was similar among groups 1 to 4; the rate was lower (p<0.05) for groups 5 and 6. In summary, synthesis of secreted and cellular proteins was greatest for porcine preantral and early antral follicles, respectively.

    This abstract is being presented on Sunday, August 1 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.