Thoracic stimulation and prolactin secretion

Current Insights in Prolactin Signaling and Ovulatory Function

Prolactin (PRL) is a pleiotropic hormone released from lactotrophic cells of the anterior pituitary gland that also originates from extrapituitary sources and plays an important role in regulating lactation in mammals, as well as other actions. Acting in an endocrine and paracrine/autocrine manner, PRL regulates the hypothalamic-pituitary-ovarian axis, thus influencing the maturation of ovarian follicles and ovulation. This review provides a detailed discussion of the current knowledge on the role of PRL in the context of ovulation and ovulatory disorders, particularly with regard to hyperprolactinemia, which is one of the most common causes of infertility in women. Much attention has been given to the PRL structure and the PRL receptor (PRLR), as well as the diverse functions of PRLR signaling under normal and pathological conditions. The hormonal regulation of the menstrual cycle in connection with folliculogenesis and ovulation, as well as the current classifications of ovulation disorders, are also described. Finally, the state of knowledge regarding the importance of TIDA (tuberoinfundibular dopamine), KNDγ (kisspeptin/neurokinin B/dynorphin), and GnRH (gonadotropin-releasing hormone) neurons in PRL- and kisspeptin (KP)-dependent regulation of the hypothalamic-pituitary-gonadal (HPG) axis in women is reviewed. Based on this review, a rationale for influencing PRL signaling pathways in therapeutic activities accompanying ovulation disorders is presented.

Treatment of Prolactinoma

Prolactinomas are the commonest form of pituitary neuroendocrine tumor (PitNET), representing approximately half of such tumors. Dopamine agonists (DAs) have traditionally been the primary treatment for the majority of prolactinomas, with surgery considered the second line. The aim of this review is to examine the historical and modern management of prolactinomas, including medical therapy with DAs, transsphenoidal surgery, and multimodality therapy for the treatment of aggressive prolactinomas and metastatic PitNETs, with an emphasis on the efficacy, safety, and future directions of current therapeutic modalities. DAs have been the mainstay of prolactinoma management since the 1970s, initially with bromocriptine and more recently with cabergoline. Cabergoline normalizes prolactin in up to 85% of patients and causes tumor shrinkage in up to 80%. Primary surgical resection of microprolactinomas and enclosed macroprolactinomas performed by experienced pituitary neurosurgeons have similar remission rates to cabergoline. Aggressive prolactinomas and metastatic PitNETS should receive multimodality therapy including high dose cabergoline, surgery, radiation therapy (preferably using stereotactic radiosurgery where suitable), and temozolomide. DAs remain a reliable mode of therapy for most prolactinomas but results from transsphenoidal surgery in expert hands have improved considerably over the last one to two decades. Surgery should be strongly considered as primary therapy, particularly in the setting of microprolactinomas, non-invasive macroprolactinomas, or prior to attempting pregnancy, and has an important role in the management of DA resistant and aggressive prolactinomas.

Unusual case presentation of lichen simplex chronicus, Hodgkin's lymphoma, and nonpuerperal hyperprolactinemia-galactorrhea

OBJECTIVE

To report the association of nonpuerperal galactorrhea and severe pruritus with clinical stage IIB Hodgkin's lymphoma.

METHODS

We present a detailed history, findings on physical examination, laboratory data, and results of diagnostic imaging in a 25-year-old woman. A review of the related literature and speculations about possible etiologic factors for this association are provided.

RESULTS

Dermatologic evaluation of the patient revealed lichen simplex chronicus with multiple excoriations on the anterior chest area and lower extremities. High serum prolactin concentrations and easily expressible galactorrhea were present. Magnetic resonance imaging of the sella with 1-mm cuts, however, revealed a normal pituitary gland. Computed tomography showed multiple enlarged mediastinal lymph nodes, and a left supraclavicular lymph node biopsy revealed the presence of Reed-Sternberg cells and lymphocyte alterations consistent with the diagnosis of Hodgkin's lymphoma. After one cycle of chemotherapy for management of the lymphoma, parallel reductions in serum prolactin concentrations and galactorrhea were noted.

CONCLUSION

Possible causes for this syndrome include afferent mammary nerve stimulation resulting from scratching of pruritic skin and cytokine-induced hypersecretion of prolactin attributable to the lymphoma. Although uncommon, this syndrome may serve as an important harbinger of developing Hodgkin's lymphoma, and its disappearance may signify a therapeutic response.