title: Assessment of lactotroph axis functionality in mice: longitudinal monitoring of PRL secretion by ultrasensitive-ELISA.
abstract: The pattern of prolactin (PRL) secretion depends on the physiological state. Due to insufficient detection sensitivity of existing assays, the precise description of these patterns in mice is lacking. We described an ultrasensitive ELISA assay that can detect mouse PRL in small fractions of whole blood, allowing longitudinal studies of PRL secretion profiles in freely moving mice. Over a 24-hour period, males displayed no oscillation in PRL levels, whereas virgin and lactating females showed large pulses. Peaks of PRL secretion reached 30-40 ng/mL in lactating female mice and rarely exceeded 10 ng/mL in virgin females. These pulses of PRL in lactating females were associated with suckling. The return of pups after an experimental 12-hour weaning induced a pulse of PRL release, reaching 100 ng/mL. This approach also enabled us to assess the inhibitory tone from hypothalamic dopamine neurons on PRL secretion. We used a dopamine D2 receptor antagonist to relieve pituitary lactotrophs from the tuberoinfundibular dopaminergic inhibitory tone and demonstrate a D2-induced PRL rise that can be used to evaluate both the secretory capacity of lactotrophs and the magnitude of the inhibitory tone on pituitary PRL release. We demonstrate that, although lactotroph function is altered to enhance chronic PRL output, their secretory response to acute stimulus is not modified during lactation and that chronic hyperprolactinemia is linked to a lower inhibitory tone. The combination of a sensitive PRL ELISA and administration of D2 receptor antagonist provide a unique opportunity to investigate the function and plasticity of the lactotroph axis in freely moving mice.
authors: Unité Mixte de Recherche-5203 (A.G., N.R., K.A., X.B., P.M., A.O.M.), Centre National de la Recherche Scientifique, Institut de Génomique Fonctionnelle, INSERM (A.G., N.R., K.A., X.B., P.M., A.O.M.), Unité 661, and Unité Mixte de Recherche-5203 (A.G., N.R., K.A., X.B., P.M., A.O.M.), Universités de Montpellier 1 and 2, F-34000 Montpellier, France; School of Biomedical Sciences (F.S., C.C.), Faculty of Medicine and Biomedical Sciences, University of Queensland, St Lucia, Queensland 4072, Australia; and Centre for Integrative Physiology (P.L.T.), University of Edinburgh, Edinburgh EH8 9XD, United Kingdom.
authors: Anne
authors: A
authors: Guillou
authors: Nicola
authors: N
authors: Romanò
authors: Frederik
authors: F
authors: Steyn
authors: Karine
authors: K
authors: Abitbol
authors: Paul
authors: P
authors: Le Tissier
authors: Xavier
authors: X
authors: Bonnefont
authors: Chen
authors: C
authors: Chen
authors: Patrice
authors: P
authors: Mollard
authors: Agnès O
authors: AO
authors: Martin
mesh_terms: D000818:Animals; D002940:Circadian Rhythm; D004298:Dopamine / Q000378:metabolism*; D065127:Dopamine D2 Receptor Antagonists / Q000494:pharmacology; D059290:Dopaminergic Neurons / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D007031:Hypothalamus / Q000166:cytology; D007774:Lactation; D052682:Lactotrophs / Q000187:drug effects / Q000378:metabolism*; D008137:Longitudinal Studies; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011388:Prolactin / Q000378:metabolism*
chemical_list: D065127:Dopamine D2 Receptor Antagonists; D011388:Prolactin; D004298:Dopamine