Regulatory effects of prolactin on breeding and migratory behaviours in birds

Abstract

Prolactin is an adenohypophyseal hormone of vertebrates produced by the neuroendocrine signaling of the hypothalamus. It plays important role in different vertebrate species and referred to as “The Parental Hormone” or “The Hormone of Maternity”. In birds the role of Prolactin is limited as the parental hormone but the behavioral functions like the regulation of season-al reproduction, combating stress of predators, nest building abilities and regulations of migratory cycle are diversified. The classical role of Prolactin in different birds’ species like pigeons and doves is secretion of crop sac “milk” after hatching of eggs and regulation of migration in different type of mi-grants. Reports have suggested that acute and chronic stressors and ener-getic constraints depress prolactin levels disrupting the parental effort in nest building, mate selection, incubation and crop milk production. Although prolactin is diverse in its function but acts through the same receptors throughout the vertebrate series. However, this review establishes that pro-lactin plays an intense role in regulating breeding behaviours and migration in birds along with the interactions of other hormones. Prolactin helps the birds to carry out wide range of behaviour and become evolutionarily suc-cessful.