Establishing a centralized data mart from the Rakai community cohort study to improve HIV research in Rakai, Uganda.

To improve timely access to quality HIV research data, the Rakai Health Sciences Program (RHSP) Data Mart was developed to store cohort study data from a legacy database platform in a modernized system using standard data management processes. The RHSP Data Mart was developed on a Microsoft SQL Server platform using Microsoft SQL Server Integration Services with custom data mappings and queries. The data mart stores 20+ years of longitudinal HIV research data and includes standard processes for managing data, data dictionary, training materials, and a library of queries to fulfill data requests and load new data from completed survey rounds. The RHSP Data Mart enables efficient querying and analysis of multidimensional research data by simplifying data integration and processing. A sustainable database platform with well-defined data management processes promotes data accessibility and reproducibility, enabling researchers to advance their understanding and management of infectious diseases.

A randomized trial on the effects of 2010 Dietary Guidelines for Americans and Korean diet patterns on cardiovascular risk factors in overweight and obese adults.

BACKGROUND: Dietary patterns that are considered healthy (eg, the Dietary Approaches to Stop Hypertension diet and Mediterranean diet) may be more successful in reducing typical cardiovascular disease risks compared to dietary patterns considered unhealthy (eg, energy-dense diets such as the typical American diet). OBJECTIVE: This study assessed the effects of a Korean diet, the 2010 Dietary Guidelines for Americans (DGA), and a typical American diet on cardiometabolic risk factors, including lipid levels and blood pressure, in overweight, non-Asian individuals in the United States with elevated low-density lipoprotein cholesterol. DESIGN/INTERVENTION: The study was a three-period crossover, controlled-feeding study from January 2012 to May 2012. Thirty-one subjects were randomly allocated to one of six possible sequential orders for consuming the three diets for 4 weeks, each separated by a 10-day break. Data analysis included 27 subjects on the Korean diet periods and 29 in the DGA and typical American diet periods. Subjects remained weight stable. MAIN OUTCOME MEASURES: Lipid profile, blood pressure, insulin, glucose, and 24-hour urinary sodium were determined at baseline and at the end of each diet period. STATISTICAL ANALYSES PERFORMED: The additive main effects multiplicative interactions model was used to test for a subject by diet interaction. Differences among diets were determined using a mixed-models procedure (PROC MIXED) with random intercept for each subject. RESULTS: Total cholesterol and low-density lipoprotein cholesterol significantly decreased on Korean (P<0.0001 and P<0.01, respectively) and DGA (P<0.01 and P<0.05, respectively) diets, but not on the typical American diet. Although an unfavorable outcome, high-density lipoprotein cholesterol significantly decreased on all three diets (Korean: P<0.0001; DGA: P<0.0001; typical American: P<0.05). No diet had a significant effect on serum triglycerides, but a slight increase in triglycerides in the Korean and decrease in the DGA resulted in a significant difference between these two diets (P<0.01). All three diets caused modest decreases in systolic and diastolic blood pressure, which reached statistical significance for DGA only (P<0.05 and P<0.01, respectively). No diet had significant effect on fasting insulin, whereas fasting glucose decreased significantly on the Korean (P<0.01) and typical American (P<0.05) diets only. Urinary sodium output decreased significantly on DGA (P<0.0001). CONCLUSIONS: After a 4-week feeding period, Korean and DGA diet patterns resulted in positive changes in cardiovascular disease risk factors.

Loss of Neuronal Phenotype and Neurodegeneration: Effects of T Lymphocytes and Brain Interleukin-2.

Loss of neuronal phenotype and reversal of neuronal atrophy have been demonstrated in different models of central nervous system (CNS) injury. These processes may be generalizable to different types of brain neurons and circuitry. The idea that some injured neurons may lose their phenotype and/or atrophy with the potential to rejuvenate is a remarkable and potentially promising form of neuronal plasticity that is not well understood. In this paper, we present some of our laboratory's basic neuroimmunology research showing that peripheral T cells entering the CNS, and brain-derived interleukin-2 (IL-2), play significant roles in these intriguing processes. Our findings suggest, for example, that T cell immunosenesence could be involved in related processes of brain aging and contribute to neurodegenerative disease. Neuroimmunological approaches may provide new insights into yet undiscovered factors and brain mechanisms that regulate changes in neuronal integrity associated with aging and disease. Such findings could have important implications for discovering more effective strategies for treating patients with neurotrauma and neurodegenerative diseases (e.g., Alzheimer's disease).

5. T cell immunity and neuroplasticity.

The proneuronal effects of T cells that impact the brain occur from both T cells trafficking into the brain, and from signals in the periphery (e.g., cytokine release and regulation). Recent data indicates that neuroimmunological changes in the brain can modify intrinsic brain processes that are involved in regulating neuroplasticity (e.g., T-cell/microglial interactions, neurotrophins, neurogenesis). We describe: 1) work from our lab and others showing that injury-induced loss of neuronal phenotype and reversal of motor neuron atrophy are associated with normal T cell immunity, and; 2) research indicating that these and other neuroimmunological processes may be generalizable to mechanisms of neuroplasticity involved in cognitive and emotional behavior. These findings are discussed in relation to our lab's working hypothesis, that T cell immunosenesence may contribute to alterations in brain neuroplasticity related to aging. Greater understanding of the role of adaptive T cell immunity on neuroplasticity could have important clinical implications for developing novel treatment strategies for neurodegenerative diseases (e.g., Alzheimer's) and brain injury (e.g., stroke, trauma).

Interleukin-2 and the septohippocampal system: intrinsic actions and autoimmune processes relevant to neuropsychiatric disorders.

The effects of IL-2 on brain development, function, and disease are the result of IL-2's actions in the peripheral immune system and its intrinsic actions in the central nervous system (CNS). Determining whether, and under what circumstances (e.g., development, acute injury), these different actions of IL-2 are operative in the brain is essential to make significant advances in understanding the multifaceted affects of IL-2 on CNS function and disease, including psychiatric disorders. For several decades, there has been a great deal of speculation about the role of autoimmunity in brain disease. More recently, we have learned a great deal about the role of cytokines on neurobiological processes, and there have been many studies that have found peripheral immune alterations in patients with neurological and neuropsychiatric diseases. Despite a plethora of published literature, almost all of this data in humans is correlative and much of the basic research has understandably relied on simpler models (e.g., in vitro models). Good animal models such as our IL-2 knockout mouse model could provide valuable new insight into understanding how the complex biology of a cytokine such as IL-2 can have simultaneous, dynamic effects on multiple systems (e.g., regulating homeostasis in the brain and immune system, autoimmunity that can affect both systems). Animal models can also provide much needed new data elucidating neuroimmunological and autoimmune processes involved in brain development and disease. Such information may ultimately provide critical new insight into the role of brain cytokines and autoimmunity in prominent neurological and neuropsychiatric diseases (e.g., Alzheimer's disease, autism, multiple sclerosis, schizophrenia).

Age and facial nerve axotomy-induced T cell trafficking: relation to microglial and motor neuron status.

Following peripheral axotomy of the facial nerve in mice, T lymphocytes cross the blood-brain-barrier (BBB) into the central nervous system (CNS), where they home to the neuronal cell bodies of origin in the facial motor nucleus (FMN) and act in concert with microglial cells to support the injured motor neurons. Several lines of evidence suggested normal aging may alter the injury-related responses of T cells, microglia, and motor neurons in this model. In this study, we therefore sought to test the hypothesis that compared to 8-week-old mice (young adult), 52-week-old mice (advanced middle age) would exhibit more neuronal damage and increased T cell trafficking into the injured FMN following facial nerve resection. Comparison of 8- and 52-week-old mice at 7, 14, 21, and 28 days post-resection of the facial nerve, confirmed our hypothesis that age influences the kinetics of CD3(+) T lymphocyte trafficking in the axotomized FMN. The peak T cell response was significantly higher, occurred later, and remained elevated longer in the injured FMN of mice in the 52 week age group. Although the kinetics of motor neuron death (identified by quantifying CD11b(+) perineuronal microglial phagocytic clusters engulfing the dead neurons at 7, 14, 21, and 28 days post-resection) differed between the age groups, motor neuron profile counts at day 28 showed that levels of cumulative motor neuron loss did not differ between the age groups. Compared to 8-week-old mice, however, there was small reduction in the mean cell size of the surviving motor neurons in the 52 week age group. Since T lymphocyte function decreases with normal aging, it will be important to determine if increased T cell trafficking into the injured CNS is a compensatory response to the decreased function of older T cells, and if these and related neuroimmunological changes are more pronounced in mice in the late stages of the life cycle.

Interleukin-2 deficiency-induced T cell autoimmunity in the mouse brain.

Interleukin-2 (IL-2) has been implicated in the pathogenesis of neurodevelopmental and neurodegenerative disorders. Studies from our lab have shown that adult IL-2 knockout (KO) mice exhibit septohippocampal pathology and related behavioral deficits. Compared to IL-2 wild-type (WT) mice, IL-2 KO mice have a marked and selective loss of septal cholinergic neurons that occurs between the third postnatal week and adulthood. Given that the development of septal neurons is completed by embryonic day 17 and that IL-2 KO mice exhibit peripheral autoimmunity that develops progressively post-weaning, our data and others led us to postulate that the loss of septal neurons in adult IL-2 KO mice is due to selective autoimmune neurodegeneration that coincides with increasing levels of peripheral autoimmunity. Thus, the present study tested the hypotheses: (1) that T cells selectively target the septum, and; (2) that T lymphocyte infiltration to the septum would correlate with peripheral autoimmune disease. We quantified CD3(+) T cells in the septum, hippocampus, and cerebellum of IL-2 KO and IL-2 WT mice at ages ranging from 2 to 14 weeks. T cells infiltrated the brains of IL-2 deficient mice, but were not selective for the septum. Brain T lymphocyte levels in IL-2 KO mice correlated positively with the degree of peripheral autoimmunity. We did not detect CD19(+) B lymphocytes, IgG-positive lymphocytes or IgG deposition indicative of autoantibodies in the brains of IL-2 KO mice. Further study is needed to understand how IL-2 deficiency-induced autoimmune T lymphocytes interact with endogenous brain cells to alter function and promote disease.

T cell memory in the injured facial motor nucleus: relation to functional recovery following facial nerve crush.

T cells have the ability to mount a memory response to a previously encountered antigen such that re-exposure to the antigen results in a response that is greater in magnitude and function. Following facial nerve transection, T cells have been shown to traffic to injured motor neurons in the facial motor nucleus (FMN) and may have the ability to promote neuronal survival and functional recovery. Previously, we demonstrated that early exposure to neuronal injury on one side of the brain during young adulthood elicited a T cell response that was greater in magnitude following exposure to the same form of injury on the contralateral side later in adulthood. Whether the T cell memory response to neuronal injury influenced functional recovery following nerve crush injury was unknown. In the current study, we tested the hypotheses that (1) transection of the right facial nerve in sensitized mice would result in faster recovery of the whisker response when the contralateral facial nerve is crushed 10 weeks later, and (2) the early recovery would be associated with an increase in the magnitude of the T cell response in the contralateral FMN following crush injury in sensitized mice. The onset of modest recovery in sensitized mice occurred between 3 and 5 days following crush injury of the contralateral facial nerve, approximately 1.5 days earlier than naïve mice, and was associated with more than a two-fold increase in the magnitude of the T cell response in the contralateral FMN following crush injury. There was no difference between groups in the number of days to full recovery. Further study of how T cell memory influences neuroregeneration may have important implications for translational research.

Influence of injury severity on the rate and magnitude of the T lymphocyte and neuronal response to facial nerve axotomy.

The temporal relationship between severity of peripheral axonal injury and T lymphocyte trafficking to the neuronal cell bodies of origin in the brain has been unclear. We sought to test the hypothesis that greater neuronal death induced by disparate forms of peripheral nerve injury would result in differential patterns of T cell infiltration and duration at the cell bodies of origin in the brain and that these measures would correlate with the magnitude of neuronal death over time and cumulative neuronal loss. To test this hypothesis, we compared the time course of CD3(+) T cell infiltration and neuronal death (assessed by CD11b(+) perineuronal microglial phagocytic clusters) following axonal crush versus axonal resection injuries, two extreme variations of facial nerve axotomy that result in mild versus severe neuronal loss, respectively, in the facial motor nucleus. We also quantified the number of facial motor neurons present at 49 days post-injury to determine whether differences in the levels of neuronal death between nerve crush and resection correlated with differences in cumulative neuronal loss. Between 1 and 7 days post-injury when levels of neuronal death were minimal, we found that the rate of accumulation and magnitude of the T cell response was similar following nerve crush and resection. Differences in the T cell response were apparent by 14 days post-injury when the level of neuronal death following resection was substantially greater than that seen in crush injury. For nerve resection, the peak of neuronal death at 14 days post-resection was followed by a maximal T cell response one week later at 21 days. Differences in the level of neuronal death between the two injuries across the time course tested reflected differences in cumulative neuronal loss at 49 days post-injury. Altogether, these data suggest that the trafficking of T cells to the injured FMN is dependent upon the severity of peripheral nerve injury and associated neuronal death.

Immunodeficiency impairs re-injury induced reversal of neuronal atrophy: relation to T cell subsets and microglia.

Following facial nerve resection in the mouse, a substantial number of neurons reside in an atrophied state (characterized by cell shrinkage and decreased ability to uptake Nissl stain), which can be reversed by re-injury. The mechanisms mediating the reversal of neuronal atrophy remain unclear. Although T cells have been shown to prevent neuronal loss following peripheral nerve injury, it was unknown whether T cells play a role in mediating the reversal of axotomy-induced neuronal atrophy. Thus, we used a facial nerve re-injury model to test the hypothesis that the reversal of neuronal atrophy would be impaired in recombinase activating gene-2 knockout (RAG-2 KO) mice, which lack functional T and B cells. Measures of neuronal survival were compared in the injured facial motor nucleus (FMN) of RAG-2 KO and wild-type (WT) mice that received a resection of the right facial nerve followed by re-injury of the same nerve 10 weeks later ("chronic resection+re-injury") or a resection of the right facial nerve followed by sham re-injury of the same nerve 10 weeks later ("chronic resection+sham"). We recently demonstrated that prior exposure to neuronal injury elicited a marked increase in T cell trafficking indicative of a T cell memory response when the contralateral FMN was injured later in adulthood. We examined if such a T cell memory response would also occur in the current re-injury model. RAG-2 KO mice showed no reversal of neuronal atrophy whereas WT mice showed a robust response. The reversal of atrophy in WT mice was not accompanied by a T cell memory response. Although the number of CD4(+) and CD8(+) T cells in the injured FMN did not differ from each other, double-negative T cells appear to be recruited in response to neuronal injury. Re-injury did not result in increased expression of MHC2 by microglia. Our findings suggest that T cells may be involved in reversing the axotomy-induced atrophy of injured neurons.

IL-15 and IL-15R alpha gene deletion: effects on T lymphocyte trafficking and the microglial and neuronal responses to facial nerve axotomy.

IL-15 is a potent T cell chemoattractant, and this cytokine and its unique alpha subunits, IL-15R alpha, can modify immune cell expression of several T cell chemokines and their receptors. Facial nerve axotomy in mice leads to T cell migration across an intact blood-brain-barrier (BBB), and under certain conditions T cells can provide neuroprotection to injured neurons in the facial motor nucleus (FMN). Although chemokines and chemoattractant cytokines are thought to be responsible for T cell migration to the injured cell bodies, data addressing this question are lacking. This study tested the hypothesis that T cell homing to the axotomized FMN would be impaired in knockout (KO) mice with the IL-15 and IL-15R alpha genes deleted, and sought to determine if microglial responsiveness and motoneuron death are affected. Both IL-15KO and IL-15R alpha KO mice exhibited a marked reduction in CD3(+) T cells and had fewer MHC2(+) activated microglia in the injured FMN than their respective WT controls at day 14 post-axotomy. Although there was a relative absence of T cell recruitment into the axotomized FMN in both knockout strains, IL-15R alpha KO mice had five times more motoneuron death (characterized by perineuronal microglial clusters engulfing dead motoneurons) than their WT controls, whereas dead neurons in IL-15KO did not differ from their WT controls. Further studies are needed to dissect the mechanisms that underlie these observations (e.g., central vs. peripheral immune contributions).

Prior facial motor neuron injury elicits endogenous T cell memory: relation to neuroregeneration.

We tested the hypotheses that prior injury to the facial motor nucleus (FMN) would elicit a more robust T cell response in the opposite FMN when the contralateral facial nerve was injured later in life, and that this would result in improved neuroregeneration. Measures of T cell, neuronal and microglial status were compared in sensitized mice (right facial nerve transection followed by contralateral facial nerve transection 9.5 weeks later) and naïve mice (sham surgery of the right facial nerve followed by contralateral facial nerve transection 9.5 weeks later) following axotomy of the contralateral facial nerve. At day 14 post-axotomy, sensitized mice exhibited nearly a two-fold increase in T cells in the FMN compared to naïve mice. There were no differences between the groups in levels of dead neurons and NeuN expression by surviving motor neurons at day 14, or motor neuron survival and cell area at day 49 post-axotomy. Measures of microglial responsiveness did not differ between the groups. Further study is needed to delineate the role of endogenous T cell memory in neuronal injury and regeneration.

Endogenous T lymphocytes and microglial reactivity in the axotomized facial motor nucleus of mice: effect of genetic background and the RAG2 gene.

Following facial nerve axotomy in mice, peripheral T cells home to the injured facial motor nucleus (FMN) where they may influence the glial response. Interactions between T cells and microglia, which proliferate in response to axotomy, appear to confer neuroprotection to injured motoneurons. The primary objective of this study was to determine whether T lymphocytes could influence the microglial reaction to motoneuron injury. These experiments tested the hypotheses that (1) C57BL/6 (B6) and 129 mice, inbred strains which have high and low levels of astroglial reactivity in the axotomized FMN, respectively, would also exhibit high and low levels of T cell infiltration, and (2) that these differences would correspond with levels of microglial reactivity and neuronal regeneration. Thus, we compared the response to facial nerve axotomy in B6, 129, and immunodeficient RAG2 knockout (RAG2 KO) mice on these two backgrounds at 14 day post-axotomy for differences in levels of 1) CD3+ T cell infiltration; (2) major histocompatibility complex II (MHC2) expression by microglia; (3) perineuronal microglial phagocytic clusters, an indirect measure of neuronal death; and (4) overall microglial activity as assessed by CD11b expression. To examine the inheritance pattern of the abovementioned neuroimmune measures, we also made assessments in B6x129 F1 generation mice. B6 and 129 mice displayed high and low levels of T cell infiltration to the affected FMN and low and high MHC2 expression, respectively. Levels of microglial activity did not differ between the two strains. In immunodeficient RAG2 KO mice on both backgrounds, the number of MHC2+ microglia did not differ from their immunologically normal background controls. Moreover, deletion of either the RAG2 or RAG1 genes in B6 mice was not associated with increased neuronal death at day 14 post-axotomy, as we had previously found in B6 mice with the severe combined immunodeficiency (SCID) mutation. Contrary to our hypothesis, the paucity of T cells in the affected FMN of the 129 mice was associated with less neuronal death when compared to B6 mice, which showed a robust T cell response. Moreover, the data suggest that parameters of the central and peripheral immune responses to axotomy are independently regulated. Assessments in B6x129 F1 generation mice revealed dominant phenotypes for both T cell infiltration and neurodegeneration, whereas both strains contributed significantly to the phenotype for MHC2 expression. Our findings suggest that (1) T cells do not appear to modify measures of microglial reactivity in the axotomized FMN; and (2) the impact of T cells on injured motoneurons in immunologically intact mice and in immunodeficient mice grafted with T cells by adoptive transfer may be different. Further study is required to understand the role of T cells following motoneuron injury in immunologically intact mice and how the seemingly divergent effects of T cells in intact and immunodeficient mice might provide insight into their role in neuronal injury and repair.

Changes in hippocampal IL-15, related cytokines, and neurogenesis in IL-2 deficient mice.

Previous studies have demonstrated that interleukin-2 knockout (KO) mice exhibit alterations in hippocampal cytoarchitecture. Several lines of evidence suggest that these variations may result from immune dysregulation and/or autoimmunity. Thus, this study sought to compare adult IL-2 KO mice and wild-type littermates (8-12 weeks of age), the age where differences in hippocampal cytoarchitecture have previously been observed, for differences in measures of neuroimmunological status in the hippocampus. Furthermore, because IL-15 shares the same receptor subunits for signal transduction as IL-2 (IL-2/15Rbeta and gammac) that are enriched in the hippocampus and may induce inflammatory processes in IL-2 KO mice, we sought to test the hypothesis that IL-15 is elevated in the hippocampus of IL-2 KO mice. Compared to wild-type mice, IL-2 KO mice exhibited increased hippocampal protein concentrations of IL-15 as well as IL-12, IP-10, and MCP-1. These cytokine changes, however, did not correlate with levels in the peripheral circulation, and there were no T cells or an increase in MHCII-positive microglia in the hippocampus of IL-2 KO mice. Since elevated levels of certain inflammatory cytokines may impair hippocampal neurogenesis, we also tested the hypothesis that changes in neuroimmunological status would be associated with reductions in neurogenesis of neurons in the dentate gyrus of IL-2 KO mice. Contrary to this hypothesis, compared to wild-type mice, male IL-2 KO mice exhibited increased neurogenesis in both the infrapyramidal and suprapyramidal limbs of the granule cell layer of the dentate gyrus, differences that were not observed between females. These findings indicate that IL-2 gene deletion alters the neuroimmunological status of the mouse hippocampus through a dysregulation of cytokines produced by CNS cells, and in males, these changes are associated with increased hippocampal neurogenesis.

IL-2 deficiency results in altered septal and hippocampal cytoarchitecture: relation to development and neurotrophins.

We have found previously that brain IL-2 receptors are enriched in the hippocampal formation, and that loss of this cytokine results in cytoarchitectural alterations in the hippocampus and septum and related behavioral changes in IL-2 knockout (IL-2 KO) mice. These alterations included decreased cholinergic somata in the medial septum/vertical limb of the diagonal band of Broca (MS/vDB) and decreased distance across the infrapyramidal (IP) granule cell layer (GCL) of the dentate gyrus (DG). To extend our previous findings, several experiments were conducted comparing IL-2 KO mice and wild-type littermates to determine (1) whether the GABAergic projection neurons of IL-2 KO mice in this region were also affected; (2) if the reduction in septal cholinergic projection neurons found in adult IL-2 KO mice is present at weaning (and prior to the development of peripheral autoimmune disease); and (3) if loss of IL-2 may result in changes in the neurotrophins, brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), involved in maintenance of hippocampal neurons. No differences in GABAergic neurons in the MS/vDB were found in adult mice, and the reduction in cholinergic neurons seen in adult IL-2 KO mice was not found in animals at postnatal day 21. The number of neurons in the IP-GCL was also significantly reduced. Compared to wild-type mice, IL-2 KO mice had significantly reduced concentration of BDNF protein and increased concentrations of NGF. These data suggest that the septohippocampal neuronal loss in IL-2 KO mice is selective for the cholinergic neurons and appears to be due to a failure in neuronal maintenance/survival that may be, in part, associated with changes in neurotrophins.

Effect of adrenalectomy on mating-induced prolactin surges and pseudopregnancy in the female rat.

In the estrous female rat, mating stimulation induces an acute surge of prolactin (PRL) within 20 min after mating followed by the onset of twice-daily PRL surges which persist for an 8- to 13-day period of acyclicity called pseudopregnancy. In Experiment 1, we examined whether the release of adrenal hormones after mating modulates mating-induced PRL secretion during the first 38 h after mating. Ovariectomized females were adrenalectomized (Adx) or sham-operated (Sham) and were implanted with jugular vein catheters 2 days later. They were given estrogen and progesterone and mated 6 days after the last surgery until they received 15 intromissions or 15 mounts-without-intromission from a male. Blood samples were collected beginning 20 min before mating at 23:00 h and continuing for 38 h. Plasma PRL concentrations were measured using radioimmunoassay. Mating that included intromissions induced an acute (20-min) PRL response which was higher in Adx than in Sham animals, and advanced in the Adx animals in the onset of the first daily PRL surge to 10:00 h, some 18 h before the surge was observed at 04:00 h in the Sham-mated animals. A small but measurable nocturnal surge was observed in Adx and Sham groups 18-24 h later at 04:00-10:00 h. In Experiment 2, Adx- and Sham-cycling animals received 5 (5I) or 7 (7I) intromissions from a male 12-16 days after surgery. Adx animals receiving 5I showed a significantly higher incidence of pregnancy or pseudopregnancy (%P/PSP) than did Sham 5I animals, while there was no difference in %P/PSP in the 7I groups. We conclude that adrenal gland secretions normally suppress plasma PRL concentrations immediately post-mating and before the onset of the nocturnal mating-induced PRL surge and also inhibit pseudopregnancy when females receive a subthreshold number of intromissions normally required for its induction.