title: Changes in PACAP immunoreactivity in human milk and presence of PAC1 receptor in mammary gland during lactation.
abstract: Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with widespread occurrence in the nervous system and peripheral organs, including the mammary gland. Previously, we have shown that PACAP38 is present in the human milk at higher levels than in respective blood samples. However, it is not known how PACAP levels and the expression of PAC1 receptor change during lactation. Therefore, the aim of our study was to investigate PACAP38-like immunoreactivity (PACAP38-LI) in human colostrums and transitional and mature milk during lactation and to compare the expression of PAC1 receptors in lactating and non-lactating mammary glands. We found that PACAP38-LI was significantly higher in human colostrum samples than in the transitional and mature milk. PACAP38-LI did not show any significant changes within the first 10-month period of lactation, but a significant increase was observed thereafter, up to the examined 17th month. Weak expression of PAC1 receptors was detected in non-lactating sheep and human mammary glands, but a significant increase was observed in the lactating sheep samples. In summary, the present study is the first to show changes of PACAP levels in human milk during lactation. The presence of PACAP in the milk suggests a potential role in the development of newborn, while the increased expressions of PAC1 receptors on lactating breast may indicate a PACAP38/PAC1 interaction in the mammary gland during lactation.
authors.affiliation: Department of Anatomy, PTE-MTA Lendulet PACAP Research Group, University of Pecs, 7624 Pecs, Szigeti ut 12, Hungary.
authors.forename: Katalin
authors.initials: K
authors.lastname: Csanaky
authors.forename: Eszter
authors.initials: E
authors.lastname: Banki
authors.forename: Krisztina
authors.initials: K
authors.lastname: Szabadfi
authors.forename: Dora
authors.initials: D
authors.lastname: Reglodi
authors.forename: Ibolya
authors.initials: I
authors.lastname: Tarcai
authors.forename: Levente
authors.initials: L
authors.lastname: Czegledi
authors.forename: Zsuzsanna
authors.initials: Z
authors.lastname: Helyes
authors.forename: Tibor
authors.initials: T
authors.lastname: Ertl
authors.forename: Judit
authors.initials: J
authors.lastname: Gyarmati
authors.forename: Zalan
authors.initials: Z
authors.lastname: Szanto
authors.forename: Istvan
authors.initials: I
authors.lastname: Zapf
authors.forename: Erika
authors.initials: E
authors.lastname: Sipos
authors.forename: Seiji
authors.initials: S
authors.lastname: Shioda
authors.forename: Andrea
authors.initials: A
authors.lastname: Tamas
mesh_terms: D000818:Animals; D001940:Breast / Q000737:chemistry* / Q000502:physiology; D003126:Colostrum / Q000737:chemistry*; D005260:Female; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D007774:Lactation / Q000502:physiology*; D008321:Mammary Glands, Animal / Q000737:chemistry* / Q000502:physiology; D008895:Milk, Human / Q000737:chemistry*; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide / Q000032:analysis*; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I / Q000032:analysis* / Q000096:biosynthesis / Q000235:genetics; D034561:Sheep, Domestic / Q000502:physiology*; D013045:Species Specificity
chemical_list: C495401:ADCYAP1 protein, human; D051219:Pituitary Adenylate Cyclase-Activating Polypeptide; D051237:Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I