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   The secretions of the pituitary gland affect a wide range of psychological processes. In fact, the smaller pituitary volume itself has to do with bipolar disorder, eating disorder and obsessive-compulsive disorder. Let us discuss the impact of the pituitary secretions on the behaviour.
Adrenocorticotropic hormone (ACTH): The pituitary gland secrets ACTH which regulates hypothalamic-pituitary-adrenal (HPA) axis activity. Abnormalities of HPA axis are evident in psychosis. Increase in the levels of cortisol and ACTH has been witnessed in patients experiencing first psychotic episode. Increase in the volume of the pituitary gland leads to increase in the size and number of corticotroph cells producing ACTH. Hyperactivity of the HPA axis is associated with major depression. This increase in the volume of pituitary is also seen in those with lack of negative inhibitory feedback. This increase in the females leads to increase in luteinizing hormone (LH) and follicle-stimulating hormone (FSH) during puberty and menstrual cycle. Psychotic patients have reduced levels of LH and FSH. On the contrary, decrease of pituitary volume has been associated with mental disorders such as bipolar disorder, eating disorder, and obsessive-compulsive disorder.
In our day-to-day life we do come across situations posing difficult cognitive tasks such as addressing a small gathering, facing a cross-examination and so forth. Such situations activates HPA axis causing increased cortisol in blood, saliva and urine. The whole mechanism operates like this. Perception of a stressful stimulus activates hypothalamus to release corticotropin-releasing hormone. This, in turn, stimulates the anterior pituitary to release ACTH. When ACTH reaches the adrenal cortex it makes the outer layer of adrenal gland to release cortisol. According to Dickerson and Kemeny (2002) the peak cortisol response takes place 20-40 minutes after the onset of acute stressor and return to baseline levels happens 40-60 minutes after the end of the stressor.
Marital conflict is a common observation in most of the societies. Studies exploring the effect of positive and negative behaviours during marital conflict on changes in ACTH and cortisol have reported adaptive physiological responses when one constructively engages in discussions during interpersonal conflict. Hostile and negative behaviour during conflict is coupled with increased level of ACTH, which triggers production of cortisol. Studies show that compared to positive behaviours negative behaviours has considerable effect on HPA axis.
Prolactin: Disruption of the normal prolactin secretion results in hyperprolactinaemia. Hyperprolactinaemia is the common endocrine disorder of the hypothalamic-pituitary axis. It can result into short-term sexual dysfunction besides adversely affecting bone mineral density. A proposed explanation for this is the partial suppression of gonadotropin-releasing hormone (GnRH), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone pulsatility on the gonad. In females, hyperprolactinaemia is associated with vaginal dryness or lack of swelling. Anorgasmia can be seen in both, males as well as females. Prolactin is secreted from the anterior pituitary gland. It is affected depending on the nature of the stressors. Dopamine has an inhibitory effect on prolactin secretion. Dopamine mediates the effect of stress on prolactin secretion. As it prepares breast tissue for lactation and stimulates milk secretion in females in the perinatal period, variation in the level of secretion is likely to affect milk release.