Role of orexin A in growth hormone (GH) secretion in lambs born under different photoperiod conditions - in vitro study

Orexin and neuropeptide Y: Tissue specific expression and immunoreactivity in the hypothalamus and preoptic area of the cichlid fish Cichlasoma dimerus

“…On the other hand, orexin receptors have been localized in human, rat, sheep and Xenopus laevis pituitary cells (Date et al, 2000;Kaminski and Smolinska, 2012) and central administration of orexin and a posterior analysis of pituitaries for hormone gene expression in rats indicates a possible effect of this neuropeptide as a pituitary hormone modulator (Kohsaka et al, 2001;Pu et al, 1998;Seoane et al, 2004). Moreover, Molik et al (2008) using sheep pituitary explants demonstrated that orexin modulates GH and prolactin secretion. The presence of orexin-A fibers observed in C. dimerus neurohypophysis in addition to the above results cited in other vertebrates suggest that orexin may regulate the synthesis of pituitary hormones and/or hormone release.…”

Hypocretins, sleep, and maternal behavior

“…The effects of HCRT on prolactin synthesis and secretion remain uncertain and subject to debate as limited research has been conducted in the context of lactation. To our knowledge, only one study, conducted by Molik et al (2008), has investigated the impact of HCRT-1 on prolactin release using in vitro pituitary explants from lactating sheep. The results suggest that HCRT-1 directly stimulates prolactin release from lactotroph cells (Molik et al, 2008).…”

“…To our knowledge, only one study, conducted by Molik et al (2008), has investigated the impact of HCRT-1 on prolactin release using in vitro pituitary explants from lactating sheep. The results suggest that HCRT-1 directly stimulates prolactin release from lactotroph cells (Molik et al, 2008). On the other hand, in non-lactating females, while there is evidence that HCRT stimulate prolactin release (Kohsaka et al, 2001), it has also been shown that HCRT reduce the expression of this hormone in lactotrope cells (Fujisawa et al, 2019).…”