Hamster thecal cells express muscle characteristics

Journal Article · Mon Aug 01 00:00:00 EDT 1988 · Biol. Reprod.; (United States)

DOI:https://doi.org/10.1095/biolreprod39.1.119· OSTI ID:6499879

Self, D A; Schroeder, P C; Gown, A M

Contraction of the follicular wall about the time of ovulation appears to be a coordinated event; however, the cells that mediate it remain poorly studied. We examined the theca externa cells in the wall of hamster follicles for the presence of a functional actomyosin system, both in developing follicles and in culture. We used a monoclonal antibody (HHF35) that recognizes the alpha and gamma isoelectric variants of actin normally found in muscle, but not the beta variant associated with non-muscle sources, to evaluate large preovulatory follicles for actin content and composition. Antibody staining of sectioned ovaries showed intense circumferential reactivity in the outermost wall of developing follicles. Immunoblots from two-dimensional gels of theca externa lysates demonstrated the presence of the two muscle-specific isozymes of actin. Immunofluorescence of cultured follicular cells pulse-labeled with (3H) thymidine (for autoradiographic detection of DNA replication) revealed the presence, in many dividing cells, of actin filaments aligned primarily along the longitudinal axis of the cells. In cultures exposed to the calcium ionophore A23187 (10(-4) M) for varying periods (5 min to 1 h), contraction of many individual muscle-actin-positive cells was observed. Immunofluorescence of these cells, fixed immediately after ionophore-induced contraction, revealed compaction of the actin filaments. Our findings demonstrate that the cells of the theca externa contain muscle actins from an early stage and that these cells are capable of contraction even while proliferating in subconfluent cultures. They suggest that follicular growth may include a naturally occurring developmental sequence in which a contractile cell type proliferates in the differentiated state.

• Research Organization: Washington State Univ., Pullman (USA)
• OSTI ID: 6499879
• Journal Information: Biol. Reprod.; (United States), Vol. 39:1
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ACTIN
BIOSYNTHESIS
ANIMAL CELLS
CELL PROLIFERATION
MUSCLES
CONTRACTION
AUTORADIOGRAPHY
CELL CULTURES
DNA REPLICATION
FLUORESCENCE
HAMSTERS
MONOCLONAL ANTIBODIES
OVARIES
THYMIDINE
TRITIUM COMPOUNDS
TWO-DIMENSIONAL ELECTROPHORESIS
ANIMALS
ANTIBODIES
AZINES
BODY
ELECTROPHORESIS
FEMALE GENITALS
GONADS
HETEROCYCLIC COMPOUNDS
LABELLED COMPOUNDS
LUMINESCENCE
MAMMALS
NUCLEIC ACID REPLICATION
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
PROTEINS
PYRIMIDINES
RIBOSIDES
RODENTS
SYNTHESIS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques