Bioscientifica Proceedings

Summary. Studies of isolated cell types from sheep follicles revealed several functional changes which occur during follicular maturation. Cyclic AMP production by granulosa cells from the smallest follicles studied (1–3 mm diameter) was stimulated by FSH but not by hCG, suggesting functional FSH receptors at this early stage of differentiation. Medium-sized follicles (4–6 mm) responded to both FSH and hCG. Granulosa cells were unable to synthesize a...

Summary. Southern blotting of bovine genomic DNA indicated the presence of at least 3 bovine tIFN genes. The full DNA sequence of one of these genes, thought to be expressed in trophoblast, has been determined, including 193 bp of 5' non-coding region. The inferred amino acid sequence of bovine tIFN is more similar to ovine tIFN (80%) than to bovine IFN-αII (70%). The 5' flanking sequence has some similarity with bovine IFN-&#94...

The corpus luteum is a transient gland, which is only functional for 17–18 days in the cyclic cow or for up to 200 days in the pregnant cow. Regression of the corpus luteum is essential for normal cyclicity as it allows the development of a new ovulatory follicle, whereas prevention of luteolysis is necessary for the maintenance of pregnancy. Evidence acquired over the past three decades indicated that PGF2α is the luteolytic hormone in ruminants. Neverthe...