Paternal Deprivation Research Articles

Early bi-parental separation or neonatal paternal deprivation in mandarin voles reduces adult offspring paternal behavior and alters serum corticosterone levels and neurochemistry

Although the effect of early social environments on maternal care in adulthood has been examined in detail, few studies have addressed the long-term effect on paternal care and its underlying neuroendocrine mechanisms. Here, using monogamous mandarin voles (Microtus mandarinus) that show high levels of paternal care, the effects of early bi-parental separation (EBPS) or neonatal paternal deprivation (NPD) on adult paternal behavior, serum corticosterone levels, and receptor mRNA expression in the nucleus accumbens (NAcc) and medial preoptic area (MPOA) were investigated. Compared to the parental care group (PC), we found that EBPS reduced crouching behavior and increased inactivity, self-grooming, and serum corticosterone levels in adult offspring; and NPD significantly reduced retrieval behavior and increased self-grooming behavior of offspring at adulthood. EBPS displayed more dopamine type I receptor (D1R) mRNA expression in the NAcc, but less oxytocin receptor (OTR) mRNA expression than PC in the MPOA. Both EBPS and NPD exhibited more mRNA expression of estrogen receptor alpha (ERα) than PC in the MPOA. In the EBPS group, increased serum corticosterone concentration was closely associated with reduced crouching behavior, and reduced expression of OTR was closely associated with altered crouching behavior and increased D1R expression. Our results provide substantial evidence that EBPS or NPD has long-term consequences and reduces paternal behavior in adult animals. Importantly the oxytocin system in the MPOA might interact with NAcc dopamine systems to regulate paternal behavior and EBPS may affect interactions between the MPOA and NAcc.

Early Paternal Deprivation Alters Levels of Hippocampal Brain-Derived Neurotrophic Factor and Glucocorticoid Receptor and Serum Corticosterone and Adrenocorticotropin in a Sex-Specific Way in Socially Monogamous Mandarin Voles

In monogamous mammals, fathers play an important role in the development of the brain and typical behavior in offspring, but the exact nature of this process is not well understood. In particular, little research has addressed whether the presence or absence of paternal care alters levels of hippocampal glucocorticoid receptor (GR) and brain-derived neurotrophic factor (BDNF), and basal levels of serum corticosterone (CORT) and adrenocorticotropin (ACTH). Here, we explored this concept using socially monogamous mandarin voles (Microtus mandarinus), a species in which fathers display high levels of paternal care toward their pups. Our immunohistochemical study shows that paternal deprivation (PD) significantly decreased levels of GR and BDNF protein in the CA1 and CA2/3 of the hippocampus. In the dental gyrus, decreases in GR and BDNF induced by PD were evident in females but not in males. Additionally, enzyme-linked immunosorbent assay results show that PD significantly upregulated levels of serum CORT and ACTH in females, but not males. These findings demonstrate that PD alters HPA axis activity in a sex-specific way. The changes in stress hormones documented here may be associated with alteration in hippocampal BDNF and GR levels.

Neuroendocrine responses to social isolation and paternal deprivation at different postnatal ages in mandarin voles

Neonatal isolation and paternal deprivation have long lasting effects on the behavior and neuroendocrine system at adulthood. Whether these effects at adulthood are induced by neonatal changes in relevant neuroendocrine parameters lead by these early-life social experiences is not well understood. Whether monogamous rodents exhibit a stress hypo-responsive period (SHRP) also remains unclear. Using the monogamous mandarin vole, we found that 30 min of isolation did not affect levels of corticosterone (CORT) and adrenocorticotropin (ACTH) at postnatal days 8, 10, and 12 displaying a SHRP, but increased these at postnatal days 4, 14, 16, and 18. Isolation increased vasopressin (AVP)-ir neurons in the paraventricular nucleus (PVN) and supraoptic nucleus (SON) from postnatal days 4 to 12, and up-regulated oxytocin (OT)-ir neurons in the PVN at postnatal days 4 and 8 and SON at postnatal day 4. Paternally deprived pups showed increase in ACTH and CORT after 30 min of social isolation from postnatal days 8 to 14, increase in AVP-ir neurons in the PVN from postnatal days 10 to 14, reduction in OT-ir neurons in the PVN from postnatal days 10 to 14 and in the SON at postnatal days 12 and 14. These results indicate that monogamous mandarin voles display a short SHRP which can be disrupted by paternal deprivation. Central AVP and OT levels may also be altered by paternal deprivation and social isolation. We propose that changes in these neuroendocrine parameters induced by early-life social experiences such as those tested here persist and result.

EPA-0178 – Father, my belly hurts!

Introduction The concept of psychosomatic family, introduced by Minuchin, refers to some family organizations that maintain and reinforce psychosomatic symptoms in their members. The literature indicates that some family factors may lead to the emergence of somatic symptoms in a child or adolescent. Objectives The main objective of this study is the case report of an adolescent with recurrent abdominal pain and its integration in the existing literature. Case report A 14 year old girl presented to the emergency department (ED) with recurrent abdominal pain. She had already been hospitalized and undergone exploratory laparoscopy surgery that excluded organic causes. During observation the pain relieved with the injection of saline solution, and the adolescent was discharged from the ED and referred for psychiatric consultation at the outpatient clinic of the Child and Adolescent Psychiatry Department. Regarding the adolescent family history, her parents divorced when she was 11 years old and her father was living in another country for 7 years, maintaining an increasingly scarce contact with the patient. The girl had feelings of abandon regarding her father. Discussion and Conclusions There is evidence that, as in this case, the families of children with recurrent abdominal pain are usually matrifocal, and virtual paternal deprivation may play a role in predisposing the onset of somatoform disorders. We also found a disturbed mother-father-child relationship with the establishment of an alliance between the mother and the adolescent, which was one of the interactions identified by Minuchin as being associated with somatization in children or adolescents.

Father Absence in the Monogamous California Mouse Impairs Social Behavior and Modifies Dopamine and Glutamate Synapses in the Medial Prefrontal Cortex

The role of the father in psycho-affective development is indispensable. Yet, the neurobehavioral effects of paternal deprivation (PD) are poorly understood. Here, we examined the behavioral consequences of PD in the California mouse, a species displaying monogamous bonding and biparental care, and assessed its impact on dopamine (DA), serotonin (5-HT), and glutamate (GLU) transmission in the medial prefrontal cortex (mPFC). In adult males, deficits in social interaction were observed, when a father-deprived (PD) mouse was matched with a PD partner. In adult females, deficits were observed when matching a PD animal with a non-PD control, and when matching 2 PD animals. PD also increased aggression in females. Behavioral abnormalities in PD females were associated with a sensitized response to the locomotor-activating effect of amphetamine. Following immunocytochemical demonstration of DA, 5-HT, and GLU innervations in the mPFC, we employed in vivo electrophysiology and microiontophoresis, and found that PD attenuated the basal activity of low-spiking pyramidal neurons in females. PD decreased pyramidal responses to DA in females, while enhancing responses to NMDA in both sexes. We thus demonstrate that, during critical neurodevelopmental periods, PD leads to sex-dependent abnormalities in social and reward-related behaviors that are associated with disturbances in cortical DA and GLU neurotransmission.

Neonatal paternal deprivation impairs social recognition and alters levels of oxytocin and estrogen receptor α mRNA expression in the MeA and NAcc, and serum oxytocin in mandarin voles

Paternal care is necessary for the healthy development of social behavior in monogamous rodents and social recognition underpins social behavior in these animals. The effects of paternal care on the development of social recognition and underlying neuroendocrine mechanisms, especially the involvement of oxytocin and estrogen pathways, remain poorly understood. We investigated the effects of paternal deprivation (PD: father was removed from neonatal pups and mother alone raised the offspring) on social recognition in mandarin voles (Microtus mandarinus), a socially monogamous rodent. Paternal deprivation was found to inhibit the development of social recognition in female and male offspring according to a habituation–dishabituation paradigm. Paternal deprivation resulted in increased inactivity and reduced investigation during new encounters with other animals. Paternal deprivation reduced oxytocin receptor (OTR) and estrogen receptor α (ERα) mRNA expression in the medial amygdala and nucleus accumbens. Paternal deprivation reduced serum oxytocin (OT) concentration in females, but had no effect on males. Our results provide substantial evidence that paternal deprivation inhibits the development of social recognition in female and male mandarin voles and alters social behavior later in life. This is possibly the result of altered expression of central OTR and ERα and serum OT levels caused by paternal deprivation.

Paternal deprivation affects the functional maturation of corticotropin-releasing hormone (CRH)- and calbindin-D28k-expressing neurons in the bed nucleus of the stria terminalis (BNST) of the biparental Octodon degus

While the critical role of maternal care on the development of brain and behavior of the offspring has been extensively studied, our knowledge about the importance of paternal care for brain development of his offspring is still comparatively scarce. The aim of this study in the biparental caviomorph rodent Octodon degus was to analyze the impact of paternal care on the development of corticotropin-releasing hormone (CRH)-expressing neurons in the bed nucleus of the stria terminalis (BNST) and hypothalamic paraventricular nucleus (PVN). Both brain areas are key players in neuronal circuits that regulate hypothalamic–pituitary–adrenal axis (HPA) activity. At the age of postnatal day (PND) 21, we found that paternal deprivation resulted in a decreased density of CRH-containing neurons in the medial, but not in the lateral BNST, whereas no changes were observed in the PVN. These deprivation-induced changes were still prominent in adulthood. At PND 21, the density of Ca-binding protein calbindin D28K (CaBP-D28K)-expressing neurons was specifically increased in the medial, but not lateral BNST of father-deprived animals. In contrast, adult father-deprived animals show significantly decreased density of CaBP-D28K-expressing neurons in the lateral, but not medial BNST. Taken together, these results may have important implications for our understanding of the experience-driven development of neural circuits that regulate HPA activity mediating acute responses to stress and chronic anxiety.

Paternal deprivation alters play-fighting, serum corticosterone and the expression of hypothalamic vasopressin and oxytocin in juvenile male mandarin voles

Although early paternal deprivation significantly affects offspring behavioral and neuroendocrine development, the link between paternal deprivation and social play behavior remains unclear. Mandarin voles (Microtus mandarinus) are socially monogamous and display bi-paternal care. The present study examined the development of social play in juvenile male mandarin voles and the paternal influence on play-fighting, vasopressin- and oxytocin-immunoreactive neurons and serum corticosterone and testosterone levels. The results show that social play was more pronounced during postnatal days 28-35, differing from the ontogenetic pattern of other forms of social behavior. On postnatal day 35, the peak in play-fighting activity, paternal deprivation reduced boxing/wrestling levels and vasopressin-immunoreactive neurons in the anterior hypothalamus and oxytocin-immunoreactive neurons in the paraventricular nucleus, but increased vasopressin-immunoreactive neurons in the paraventricular nucleus and corticosterone levels. These results suggest that mandarin voles engage in social play according to an inverted U-shaped curve in ontogeny, and paternal deprivation influences the development of offspring play-fighting; hypothalamic vasopressin, oxytocin and serum corticosterone may play a modulatory role in the alteration of play-fighting elicited by paternal deprivation; decreased play-fighting may correlate with depressed vasopressin levels in the anterior hypothalamus.

Influence of paternal deprivation on the psychosomatic development of the children

Influence of paternal deprivation on the psychosomatic development of the children

Paternal deprivation alters the development of catecholaminergic innervation in the prefrontal cortex and related limbic brain regions

The impact of paternal care on the development of catecholaminergic fiber innervations in the prefrontal cortex, nucleus accumbens, hippocampus and the amygdala was quantitatively investigated in the biparental Octodon degus. Two age (juvenile, adult) and rearing groups: (1) degus reared without father and (2) degus raised by both parents were compared. Juvenile father-deprived animals showed significantly elevated densities of TH-immunoreactive fibers in all analyzed regions, except in the orbitofrontal cortex, as compared to biparentally reared animals. This difference between the two rearing groups was still evident in adulthood in the prelimbic and infralimbic cortices and in the hippocampal formation. Interestingly, the elevated TH fiber density in both nucleus accumbens subregions was reversed in adulthood, i.e. adult father-deprived animals showed strongly reduced TH fiber densities as compared to biparentally reared animals. We show here that paternal care plays a critical role in the functional maturation of catecholaminergic innervation patterns in prefrontal and limbic brain circuits.

The effects of neonatal paternal deprivation on pair bonding, NAcc dopamine receptor mRNA expression and serum corticosterone in mandarin voles

High levels of paternal care are important for the development of social behavior in monogamous rodents. However, the effects of paternal care on the formation of pair bonding and underlying neuroendocrine mechanisms, especially the involvements of dopamine system and corticosterone, are not well understood. We investigated effects of paternal deprivation on pair bonding in mandarin voles (Microtus mandarinus), a socially monogamous rodent. Paternal deprivation was found to inhibit the formation of pair bonding in females according to partner preference tests (PPT). Paternal deprivation also reduced body contact behavior and increased aggression in males and females in PPT. During social interaction tests (SIT), paternal deprivation was found to reduce investigative and aggressive behaviors but increase body contact and self-grooming in females, and reduce staring, aggression, body contact and self-grooming in males when interacting with the opposite sex. Paternal deprivation reduced the expression of dopamine 1-type receptor (D1R) mRNA and dopamine 2-type receptor (D2R) mRNA in the nucleus accumbens of female offspring in later life, but enhanced mRNA expression of these two dopamine receptors in males. After three days of cohabitation the expression of D1R mRNA and D2R mRNA was negatively correlated for voles reared by two parents, but positively correlated in paternally deprived animals. Paternal deprivation reduced serum corticosterone levels in females but had the opposite effect in males. Three days of cohabitation did not alter corticosterone levels of PD females, but reduced it in PC females. Our results provide substantial evidence that paternal deprivation inhibits the formation of pair bonding in female mandarin voles and alters social behavior later in life. These behavioral variations were possibly associated with sex-specific alterations in the expression of two types of dopamine receptors and serum corticosterone levels induced by paternal deprivation.

Paternal Deprivation Affects the Development of Corticotrophin‐Releasing Factor‐Expressing Neurones in Prefrontal Cortex, Amygdala and Hippocampus of the Biparental Octodon degus

Although the critical role of maternal care on the development of brain and behaviour of the offspring has been extensively studied, knowledge about the importance of paternal care is comparatively scarce. In biparental species, paternal care significantly contributes to a stimulating socio-emotional family environment, which most likely also includes protection from stressful events. In the biparental caviomorph rodent Octodon degus, we analysed the impact of paternal care on the development of neurones in prefrontal-limbic brain regions, which express corticotrophin-releasing factor (CRF). CRF is a polypeptidergic hormone that is expressed and released by a neuronal subpopulation in the brain, and which not only is essential for regulating stress and emotionality, but also is critically involved in cognitive functions. At weaning age [postnatal day (P)21], paternal deprivation resulted in an elevated density of CRF-containing neurones in the orbitofrontal cortex and in the basolateral amygdala of male degus, whereas a reduced density of CRF-expressing neurones was measured in the dentate gyrus and stratum pyramidale of the hippocampal CA1 region at this age. With the exception of the CA1 region, the deprivation-induced changes were no longer evident in adulthood (P90), which suggests a transient change that, in later life, might be normalised by other socio-emotional experience. The central amygdala, characterised by dense clusters of CRF-immunopositive neuropil, and the precentral medial, anterior cingulate, infralimbic and prelimbic cortices, were not affected by paternal deprivation. Taken together, this is the first evidence that paternal care interferes with the developmental expression pattern of CRF-expressing interneurones in an age- and region-specific manner.

The Changing Role of Fatherhood: The Father as a Provider of Selfobject Functions

Fatherhood is evolving. The way that men carry out their paternal role is reflective of the historical time era in which they live, social and cultural forces, both the mother and the father's expectations for fathering behaviors, as well as the father's own innate capabilities, wishes, and desires. Fatherhood is also greatly influenced by men's relationships with their own fathers, the quality of that relationship, and the extent to which the father was emotionally available. The ever-changing role of fathers has been a challenge for the psychoanalytic literature. There is no comprehensive theoretical body of knowledge about fatherhood that takes into account the changing nature of fathering, especially considering men's desires to be emotionally responsive and nurturing parents. This article examines the changing role of the father and suggests a model of paternal involvement that expands the nurturing and available father role to include the father as a selfobject. It discusses the importance of understanding men's relationships with their fathers, a central dynamic in shaping fathers’ involvement with their children. The residual impact of paternal deprivation is explored, followed by two clinical vignettes that symbolize the search for missing selfobject functions. This article concludes by outlining clinical implications and questions to pose to assess the selfobject relationship with one's father.

Paternal deprivation prior to adolescence and vulnerability to pituitary adenomas

It has been reported that women with prolactinoma were exposed, early in life, to an environment characterized by an absent or violent father. The present study was designed to evaluate whether paternal absence or violent paternal behavior were more prevalent in patients with pituitary adenomas (prolactinoma, acromegaly, non-secreting adenoma and Cushing's disease) compared to a control population. We conducted an observational case-control multicenter study. We interviewed 395 patients with prolactinoma (296 females and 99 males), 130 with acromegaly (87 females and 43 males), 237 with non-secreting adenoma (144 females and 93 males) and 68 with Cushing's disease (61 females and 7 males) and 365 patients from the same clinics with nodular thyroid disease or lymphocytic thyroiditis with euthyroidism as controls. Violent or absent fathers were significantly more prevalent in patients with prolactinoma or acromegaly than in controls (P=0.001 and P=0.002, respectively) but not in patients with non-secreting adenoma or corticotrophinoma. Absent fathers in prolactinoma and acromegaly versus controls: P=0.001 and P=0.119. Violent fathers in prolactinoma and acromegaly versus controls: P=0.069 and P=0.001. The prevalence of absent or violent fathers was also significantly higher in prolactinoma and acromegaly when compared to non-secreting adenoma (P=0.039 and P=0.033, respectively). Paternal deprivation before adolescence may be a risk factor for prolactinoma and acromegaly but not for non-secreting pituitary adenomas or Cushing's disease.

Neonatal paternal deprivation or early deprivation reduces adult parental behavior and central estrogen receptor α expression in mandarin voles ( Microtus mandarinus)

Previous studies on parental behavior have primarily focused on maternal behavior, with little research directed at observing paternal behavior. The effects of neonatal paternal deprivation and early deprivation on adult parental behavior and estrogen receptor α (ERα) especially remain unclear. This study examined whether paternal deprivation or early deprivation has long-term effects on the parental behavior and central ERα expression of adult mandarin vole offspring. The parental behaviors of adult mandarin voles that suffered paternal deprivation or early deprivation were observed with their own pups at 0, 13 and 21 days of age. Central ERα expression was also examined in adult virgin voles with different neonatal treatments using immunocytochemistry. The results indicated that (1) levels of parental care and sociability in adult offspring were reduced due to paternal deprivation and early deprivation; (2) ERα expression in the stria terminalis (BNST), medial preoptic area (MPOA), ventromedial hypothalamic nucleus (VMH) and arcuate hypothalamic nucleus (Arc) were also reduced by paternal deprivation and early deprivation; (3) ERα expression in the BNST, MPOA, and VMH of control females was higher than that of control males, but ERα expression in the Arc was lower. Our findings show that paternal care plays an important role in the development of parental behavior in offspring. Also, because paternal deprivation and early deprivation impaired sexual differences, the alteration of parental behavior may be associated with decreased ERα expression.

Effects of neonatal paternal deprivation or early deprivation on anxiety and social behaviors of the adults in mandarin voles

This study examined whether neonatal paternal deprivation (PD: father was removed and pups were raised just by mother) or early deprivation (ED: pups were raised by both parents except separated from not only the dam but also the peers for three hours a day from PND 0 to 13) has long-term effects on anxiety and social behaviors of adult mandarin voles. Newborn mandarin voles of F2 generation were randomly assigned to one of three groups: bi-parental care (PC: pups were raised by both parents), PD and ED. The parental care behaviors of F1 generation were observed at the age of 0, 13 and 21 days (PND 0, 13, 21) of F2 generation of PC and PD groups. Moreover, each mandarin vole of F2 generation received an open field test and a social interaction test on PND 70 and PND 75, respectively. No significant differences of parental behavior were observed between mothers and fathers from PC families, showing typical parental behavior of socially monogamous rodents. In addition, no significant differences of maternal behaviors were found between mothers from PC and PD families, indicating no maternal compensation towards pups for the absence of the paternal care. In the open field test, mandarin voles from both PD and ED families displayed higher levels of anxiety and lower locomotor activity, relative to offspring of PC family. In the social interaction test, both PD and ED mandarin voles also showed lower levels of social behavior and higher levels of anxiety. Thus, both PD and ED significantly increase anxiety and reduce social behavior of adult mandarin voles, suggesting that variation in parental investment may lead to variation in anxiety and social behaviors in rodents with different mating systems.

Paternal deprivation during infancy results in dendrite- and time-specific changes of dendritic development and spine formation in the orbitofrontal cortex of the biparental rodent Octodon degus

The aim of this study in the biparental rodent Octodon degus was to assess the impact of paternal deprivation on neuronal and synaptic development in the orbitofrontal cortex, a prefrontal region which is essential for emotional and cognitive function. On the behavioral level the quantitative comparison of parental behaviors in biparental and single-mother families revealed that (i) degu fathers significantly participate in parental care and (ii) single-mothers do not increase their maternal care to compensate the lack of paternal care. On the brain structural level we show in three-week-old father-deprived animals that layer II/III pyramidal neurons in the orbitofrontal cortex displayed significantly lower spine densities on apical and basal dendrites. Whereas biparentally raised animals have reached adult spine density values at postnatal day 21, fatherless animals seem “to catch up” by a delayed increase of spine density until reaching similar values as biparentally raised animals in adulthood. However, in adulthood reduced apical spine numbers together with shorter apical dendrites were observed in father-deprived animals, which indicates that dendritic growth and synapse formation (seen in biparental animals between postnatal day 21 and adulthood) were significantly suppressed. These results demonstrate that paternal deprivation delays and partly suppresses the development of orbitofrontal circuits. The retarded dendritic and synaptic development of the apical dendrites of layer II/III pyramidal neurons in the orbitofrontal cortex of adult fatherless animals may reflect a reduced excitatory connectivity of this cortical subregion.

Paternal deprivation induces dendritic and synaptic changes and hemispheric asymmetry of pyramidal neurons in the somatosensory cortex

Similar to maternal care, paternal care is a source of neonatal sensory stimulation, which in primates and rodents has been shown to be essential for developing structure and function of sensory cortices. The aim of our study in the biparental rodent Octodon degus was to assess the impact of paternal deprivation on dendritic and synaptic development in the somatosensory cortex. We (i) quantified the amount of paternal care in relation to total parental investment and (ii) compared dendritic and synaptic development of pyramidal neurons in the somatosensory cortex of animals raised by a single mother or by both parents. On the behavioral level we show that paternal care comprises 37% of total parent-offspring interactions, and that the somatosensory stimulation provided by the fathers primarily consists of huddling, licking/grooming, and playing. On the morphological level we found that, compared with offspring raised by both parents (mother and father), the father-deprived animals displayed significantly reduced spine numbers on the basal dendrites of pyramidal neurons. Furthermore, paternal deprivation induces hemispheric asymmetry of the dendritic morphology of somatosensory pyramidal neurons. Father-deprived animals show shorter and less complex basal dendrites in the left somatosensory cortex compared with the right hemisphere. These findings indicate that paternal deprivation results in delayed or retarded dendritic and synaptic development of somatosensory circuits.

Quality of life is decreased in female patients treated for microprolactinoma

In the August issue of the European Journal Endocrinology, Kars et al. (1) reported that quality of life of female patients treated for microprolactinoma is decreased when compared with that of appropriately chosen controls. These observations were independent of the current values of serum prolactin and of current intake, or not, of dopamine agonists, their composition or dosage. The Authors speculated that the decreased quality of life might depend on the past exposure of the brain or of other tissues to hyperprolactinemia or on the disclosure of the diagnosis of a pituitary tumor. There is a third, alternative, explanation. Life events have been reported to often precede the clinical onset of prolactinomas (2, 3). Also, paternal deprivation early in life has been reported with unusual frequency in women with prolactinomas (2, 4). Both sets of observations indicate that environmental factors may play a role in the clinical expression of prolactinomas. It is, therefore, likely that prolactinomas develop preferentially in women predisposed to activate prolactin secretion in response to some stresses, either because they were primed early in life by paternal deprivation or for some other reasons. These women may also be particularly vulnerable to anxiety and depression. In short, anxiety, depression, and other features of poor quality of life may depend on pre-existent characteristics

Prolactin, psychological stress and environment in humans: adaptation and maladaptation.

Non-puerperal lactation and/or hyperprolactinemia in humans have been related to psychological variables in a variety of ways: (1) Non-puerperal nursing; (2) Pseudopregnancy; (3) Rapid weight gain; (4) Psychogenic galactorrhea; (5) Acute prolactin responses to psychological stress; (6) High prolactin levels in persons who cope passively in real life stress situations; (7) Paternal deprivation in women with pathological hyperprolactinemia; (8) Clinical onset of prolactinomas following life-events. Publications on the above subjects are scattered in the literature as curiosities, anecdotal case-reports or unexplained associations, as there is no theoretical frame of reference to accommodate them. We propose that prolactin is a component of a biological, "maternal", subroutine, adaptive to the care of the young, which promotes accumulation of fat for the extraordinary expenses of pregnancy and lactation, the production of milk and maternal behavior. In an attempt to characterize the stimuli responsible for the activation of the maternal subroutine in the absence of pregnancy we studied the hormonal profiles of female volunteers during three types of sessions under hypnosis: (1) Relaxation-only, control sessions; (2) Sessions in which a fantasy of "nursing" was induced; (3) Sessions of evocations of memories. Prolactin surges were related to the evocation, with rage, of humiliating experiences, but not with the fantasy of nursing. Cortisol surges were related to surprise and shock and were negatively associated with prolactin. In conclusion--Prolactin and cortisol are measurable markers of two different, and alternative, coping strategies to "psychological stress".