Increased Synthesis of Prolactin and Growth Hormone during Incubation in the Pituitary of Broody Nagoya Hens

Abstract

Synthesis and release rates of prolactin and growth hormone (GH) in the anterior pituitary of laying and incubating broody chickens (Nagoya breed) were determined by a disc electrophoretic technique after in vitro incubation of anterior pituitaries with a labeled amino acid. Prolactin synthesis and release were two-fold higher in incubating than in laying hens, resulting in twofold increase in the concentration of prolactin in the gland. GH synthesis was three-fold higher in incubating than in laying hens but GH release was not affected by the incubation. GH concentration in the pituitary gland also increased in incubating hens. It is suggested that these changes in hormone synthesis, release, and concentrations are related to nesting behaviour and nutritional condition of incubating hens.

Dopamine and prolactin involvement in the maternal care of chicks in the native Thai hen (Gallus domesticus)

“…A role for PRL in inducing avian parental behavior was first observed when injections of PRL induced rearing behavior in domestic chickens (Riddle et al, 1935). Thereafter, high circulating PRL concentrations were found to be associated with rearing behavior in chickens (Hoshino and Wakita, 1989;Lea et al, 1981;Sharp et al, 1979Sharp et al, , 1988, turkeys (Burke and Dennison, 1980;Proudman and Opel, 1981), mallard ducks (Boos et al, 2007;Goldsmith and Williams, 1980), swans (Goldsmith, 1982), native Thai chickens (Chaiyachet et al, 2013b), and ring doves (Buntin, 1996).…”

Neuroendocrine regulation of rearing behavior in the native Thai hen

“…Abundant evidence has linked maternal behavior in several avian species with increased PRL secretion. High PRL levels are known to be associated with brooding behavior in chickens (Sharp et al, 1979(Sharp et al, , 1988Bedrak et al, 1981;Lea et al, 1981;Hoshino and Wakita, 1989), turkeys (Burke and Dennison, 1980;Proudman and Opel, 1981), mallard ducks (Goldsmith and Williams, 1980;Boos et al, 2007), and swans (Goldsmith, 1982). The studies in which broody chickens (Sharp et al, 1979), ducks (Goldsmith and Williams, 1980), and swans (Goldsmith, 1982) have been allowed to hatch and rear the young have shown that PRL concentrations decline at the end of the incubation period.…”

Changes in expression of the prolactin and growth hormone gene during different reproductive stages in the pituitary gland of turkeys

“…However, we cannot exclude higher rates of GH turnover both within the hypophysis and the blood which might be associated with incubation behaviour. In support of the latter, Hoshino and Wakita (1989) observed a greater than three-fold increase in the synthetic rate of GH associated with incubation behaviour, whereas the rate of release was suppressed.…”

“…(Scanes, 1987), and short-term fasting results in increased GH secretion in young chickens (Scanes, 1987) and turkeys (Proudman and Opel, 1981). Since incubation behaviour is associated with aphagia and a 20-30% decrease in body weight (Zadworny et al, 1985(Zadworny et al, , 1988, it has been proposed by Hoshino and Wakita (1989) (fig 3). Similar results have been reported in the chicken (Kansaku et al, 1994).…”

“…The transition from the laying to incubating stage in bantam hens is accompanied by a ten-fold increase in the concentration of PRL mRNA (Shimada et al, 1991;Talbot et al, 1991 In addition, the enhanced release of pituitary PRL in incubating bantam hens is associated with increased proportions of PRLsecreting cells that acquire an enhanced secretory capacity (Lopez et al, 1996). The rise of circulating levels of PRL during incubation appears, therefore, to result from increased synthesis and release of pituitary PRL (Saeki and Tanabe, 1955;Cherms et al, 1962;Burke and Papkoff, 1980;Hoshino and Wakita, 1989); however, the exact mechanisms responsible for this rise are not known.…”