Chickens and turkeys exhibit a characteristic distribution of hormone-secreting cells in the pituitary. Luteinizing hormone- (LH-) and FSH-containing gonadotrophs are the only hormone-containing cell type known to be present in both the...
moreChickens and turkeys exhibit a characteristic distribution of hormone-secreting cells in the
pituitary. Luteinizing hormone- (LH-) and FSH-containing gonadotrophs are the only hormone-containing cell type known to be present in both the cephalic and caudal lobes of the anterior pituitary. Somatotrophs are largely restricted to the caudal lobe, while corticotrophs and thyrotrophs are found only in the cephalic lobe. Lactotrophs are found only in the cephalic lobe at most ages, but invade the caudal lobe during incubation behaviour. Recent studies have shown that prolactin and growth hormone may be co-localized in the same cell during incubation behaviour. This bi-hormonal cell, termed a mammosomatotroph, may be a transitional stage in the conversion of somatotrophs to lactotrophs during periods of hyperprolactinemia. To study further the production and cellular distribution of avian prolactins, we have produced highly specific monoclonal antibodies to turkey prolactin. During the screening of clones for relevant immunohistochemical staining patterns, we identified antibodies
which bound to pituitary cells in a pattern unlike that of any known avian pituitary cell type. We
report here a partial biochemical characterization of this pituitary protein, and describe changes in its immunohistochemical localization, age and reproductive state.
