Molecular determinants regulating the release of the egg during ovulation: Perspectives in piscine models

Abstract

Reproduction in bony fish, specifically in the female teleost, encompasses well-defined stages, including growth and development, final oocyte maturation and finally ovulation – a pre-requisite for forming fertilizable female gametes. The morphological changes encountered during ovulatory response engage a multitude of endocrine, autocrine, and paracrine factors. These include gonadal steroids, growth factors, inflammatory cytokines, prostaglandins, leukotrienes and matrix metalloproteinases. In recent years, the active participation of prostaglandins and their receptors in LH-dependent ovulatory action has received much attention. Considerable evidence also supports the participation of nitric oxide/nitric oxide synthase (NO/NOS) unit in regulating meiotic maturation and ovulatory cascade. However, relatively less information is available on physiological relevance, the inter-relationship and the conjoined efforts of these molecular candidates to trigger ovulation in the fish ovary. The prime objective of the present article is to summarize the potential cross-talk between major molecular candidates downstream of LH action in the follicular layer. Besides, the intraovarian role of prostaglandin (PG) vis-à-vis NO/NOS system on mammalian and teleost ovulatory response has been emphasised.

Keywords

• Luteinizing hormone (LH)
• Ovulation
• Growth factors
• Inflammatory cytokines
• Prostaglandins
• Nitric oxide