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Suppression of the hypothalamic–pituitary–adrenal (HPA) axis is a well‐characterised maternal adaptation that limits the exposure of the offspring to maternally‐derived stress hormones. This current study has investigated the possible involvement of the lactogenic hormone, prolactin, in this physiologically important adaptation. As expected, circulating prolactin levels were higher in unstressed lactating mice compared to their virgin counterparts. Interestingly however, the ability of an acute period of restraint stress to further elevate prolactin levels was diminished in the former group. The stress‐induced rise in prolactin levels in the virgin animals was concurrent with an increase in prolactin receptor activation within the adrenal cortical cells. This adrenal response was not seen in either the stressed or control lactation group, an observation that may be in part explained by the observed downregulation of prolactin receptor mRNA expression within this tissue. Further evidence of suppression of the HPA axis during lactation was revealed using in situ hybridisation to demonstrate that while acute restraint stress increased corticotrophin releasing hormone (CRH) mRNA expression in the hypothalamic paraventricular nucleus in both virgin and lactating mice, the magnitude of this response was reduced in the latter group. This potentially adaptive response did not, however, appear to result from the altered prolactin profile during lactation because it was not affected by the pharmacological suppression of prolactin secretion from the pituitary. This study therefore suggests that during lactation the response of the HPA axis to stress is suppressed at multiple physiological levels which are mediated by both prolactin‐dependent and prolactin‐independent mechanisms. [ABSTRACT FROM AUTHOR]

Background: Health intervention implementation in Aotearoa New Zealand (NZ), as in many countries globally, usually varies by ethnicity. Māori (the Indigenous peoples of Aotearoa) and Pacific peoples are less likely to receive interventions than other ethnic groups, despite experiencing persistent health inequities. This study aimed to develop an equity-focused implementation framework, appropriate for the Aotearoa NZ context, to support the planning and delivery of equitable implementation pathways for health interventions, with the intention of achieving equitable outcomes for Māori, as well as people originating from the Pacific Islands. Methods: A scoping review of the literature to identify existing equity-focused implementation theories, models and frameworks was undertaken. One of these, the Equity-based framework for Implementation Research (EquIR), was selected for adaptation. The adaptation process was undertaken in collaboration with the project's Māori and consumer advisory groups and informed by the expertise of local health equity researchers and stakeholders, as well as the international implementation science literature. Results: The adapted framework's foundation is the principles of Te Tiriti o Waitangi (the written agreement between Māori rangatira (chiefs) and the British Crown), and its focus is whānau (extended family)-centred implementation that meets the health and wellbeing aspirations, priorities and needs of whānau. The implementation pathway comprises four main steps: implementation planning, pathway design, monitoring, and outcomes and evaluation, all with an equity focus. The pathway is underpinned by the core constructs of equitable implementation in Aotearoa NZ: collaborative design, anti-racism, Māori and priority population expertise, cultural safety and values-based. Additionally, the contextual factors impacting implementation, i.e. the social, economic, commercial and political determinants of health, are included. Conclusions: The framework presented in this study is the first equity-focused process-type implementation framework to be adapted for the Aotearoa NZ context. This framework is intended to support and facilitate equity-focused implementation research and health intervention implementation by mainstream health services. [ABSTRACT FROM AUTHOR]

Tuberoinfundibular dopamine (TIDA) neurons, knownas neuroendocrine regulators of prolactin secretion from the pituitary gland, also releaseGABAwithin the hypothalamic arcuate nucleus. As these neurons express prolactin receptors (Prlr), prolactinmayregulateGABA secretion from TIDA neurons, potentially mediating actions of prolactin on hypothalamic function. To investigate whether GABA is involved in feedback regulation of TIDA neurons, we examined the physiological consequences of conditional deletion of Prlr in GABAergic neurons. For comparison, we also examined mice in which Prlr were deleted from most forebrain neurons. Both neuron-specific and GABA-specific recombination of the Prlr gene occurred throughout the hypothalamus and in some extrahypothalamic regions, consistent with the known distribution of Prlr expression, indicative of knock-out of Prlr. This was confirmed by a significant loss of prolactininduced phosphorylation of STAT5, a marker of prolactin action. Several populations of GABAergic neurons that were not previously known to be prolactin-sensitive, notably in the medial amygdala, were identified. Approximately 50% of dopamine neurons within the arcuate nucleus were labeled with a GABA-specific reporter, but Prlr deletion from these dopamine/GABA neurons had no effect on feedback regulation of prolactin secretion. In contrast, Prlr deletion from all dopamine neurons resulted in profound hyperprolactinemia. The absence of coexpression of tyrosine hydroxylase, a marker for dopamine production, in GABAergic nerve terminals in the median eminence suggested that rather than a functional redundancy within the TIDA population, the dopamine/GABA neurons in the arcuate nucleus represent a subpopulation with a functional role distinct from the regulation of prolactin secretion. [ABSTRACT FROM AUTHOR]