Sexually dimorphic effects of prolactin treatment on the onset of puberty and olfactory function in mice

The onset of puberty is associated with the psychophysiological maturation of the adolescent to an adult capable of reproduction when olfactory signals play an important role. This period begins with the secretion of the gonadotropin-releasing hormone (GnRH) from GnRH neurons within the hypothalamus. This is regulated by kisspeptin neurons that express high levels of transmembrane prolactin receptors (PRLR) that bind to and are activated by prolactin (PRL). The elevated levels of serum PRL found during lactation, or caused by chronic PRL infusion, decreases the secretion of gonadotropins and kisspeptin and compromised the estrous cyclicity and the ovulation. In the present work, we aimed to evaluate the effects of either increased or decreased PRL circulating levels within the peripubertal murine brain by administration of PRL or treatment with cabergoline (Cab) respectively. We showed that either treatment delayed the onset of puberty in females, but not in males. This was associated with the augmentation of the PRL receptor (Prlr) mRNA expression in the arcuate nucleus and decreased Kiss1 expression in the anteroventral periventricular zone. Then, during adulthood, we assessed the activation of the mitral and granular cells of the main (MOB) and accessory olfactory bulb (AOB) by cFos immunoreactivity (ir) after the exposure to soiled bedding of the opposite sex. In the MOB, the PRL treatment promoted an increased cFos-ir of the mitral cells of males and females. In the granular cells of male of either treatment an augmented activation was observed. In the AOB, an impaired cFos-ir was observed in PRL and Cab treated females after exposure to male soiled bedding. However, in males, only Cab impaired its activation. No effects were observed in the AOB-mitral cells. In conclusion, our results demonstrate that PRL contributes to pubertal development and maturation of the MOB-AOB during the murine juvenile period in a sex-dependent way.

The value of prolactin in predicting prolactinοma in hyperprolactinaemic polycystic ovarian syndrome

BACKGROUND

To identify a serum prolactin (PRL) cut-off value indicative of a PRL-producing adenoma in women with polycystic ovarian syndrome (PCOS) and hyperprolactinaemia and characterize such patients.

MATERIALS AND METHODS

In the present retrospective case-control study, the medical records of 528 PCOS women were reviewed. Pituitary magnetic resonance imaging (MRI) was performed in PCOS patients with PRL levels ≥94.0 ng/mL and/or symptoms suspicious of a pituitary adenoma (PA). Prolactinoma diagnosis was made in the presence of an MRI-identifiable PA with biochemical and radiological response to dopamine agonists. Receiver operating characteristic (ROC) curve analysis was performed to determine a serum PRL threshold that could identify hyperprolactinaemic PCOS subjects with prolactinomas. Clinical, metabolic and endocrine parameters were also analysed.

RESULTS

Among 528 patients with PCOS, 60 (11.4%) had elevated PRL levels. Of 44 (73.3%) patients who had pituitary imaging, 19 had PAs, 18 normal MRI and 7 other abnormalities. Patients harbouring prolactinomas had significantly higher PRL levels compared to patients without adenomas (median PRL 95.4 vs 49.2 ng/mL, P < .0001). A PRL threshold of 85.2 ng/mL could distinguish patients with prolactinomas with 77% sensitivity and 100% specificity [Area Under the curve (AUC) (95%) 0.91(0.8-1.018), P = .0001]. PCOS women with prolactinomas were younger and had lower LH levels compared to women without prolactinomas.

CONCLUSIONS

In women with PCOS, PRL levels exceeding 85.2 ng/mL are highly suggestive of a prolactinoma warranting pituitary imaging. Pituitary MRI could also be considered in young PCOS patients with milder PRL elevation and low LH levels.

Sudden death of a middle aged woman with a series of undiagnosed gynaecologic diseases

Gynaecologic diseases unrelated to pregnancy are not generally associated with sudden death, which limits the number of case reports published in the field of forensic medicine. Presented in this paper is a fatal case in a middle aged woman with an early stage endometrial cancer and a series of gynaecologic diseases, in whom such typical features of sudden death were not applicable. Forensic autopsy revealed the hypoplasia of left circumflex coronary artery, Stage 1B endometrial cancer, endometriosis, polycystic ovary syndrome (PCOS) and micro pituitary adenoma, whereas histochemical analyses confirmed hyperprolactinemia and hyperestradiolemia. It was considered that the hypoplasia of coronary artery, chronic anaemia and electrolyte imbalance due to endometrial cancer all collaborated to induce acute cardiac failure. The association between prolactinoma, PCOS and endometrial cancer was also suggested, though they are rarely observed synchronously. It was speculated that the deceased had been anaemic for a substantial period of time and lacked clear subjective symptoms, which made the antemortem diagnosis of her underlying diseases difficult. Forensic pathologists must always consider the possibility of gynaecologic diseases taking significant part in a fatal cause of reproductive-aged women.

Reference intervals for follicle-stimulating hormone, luteinizing hormone and prolactin in children and young adults on the bioMérieux Mini-Vidas system

We measured serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and prolactin concentrations on a bioMérieux Mini Vidas system in a pediatric population ranging in age from 1 to 19 years. Reference intervals were established separately for females and males, with stratification by age group and by Tanner's pubertal stage. FSH values were higher in females than in males, and were lowest in both sexes of age class 2 (4–8 years), increasing thereafter to the upper limit for stage PIV (females) and stage PV (males). LH values showed a similar pattern of change: concentrations were lowest for class 1 (1–3 years) and class 2 (4–8 years), and highest for stage PII (females) and stage PV (males). No significant difference was observed according to gender. Prolactin values did not differ markedly according to gender or pubertal status.

Clin Chem Lab Med 2007;45:541–5.

Intractable early childhood obesity as the initial sign of insulin resistant hyperinsulinism and precursor of polycystic ovary syndrome

OBJECTIVE

We report that intractable early childhood obesity may be associated with severe insulin resistance syndromes (pseudo-Cushing's syndrome and pseudo-acromegaly) and precede polycystic ovary syndrome (PCOS).

STUDY DESIGN/RESULTS

Patient 1 had prepubertal obesity followed by early puberty and was diagnosed with pseudo-Cushing's syndrome and insulin resistance at 10.3 years. Oligomenorrhea, androgen excess, and type 2 diabetes mellitus (DM2) emerged at 13.5 years. Patient 2 developed intractable prepubertal obesity followed by atypical true sexual precocity and pseudo-Cushing's syndrome in early childhood. By 11.3 years, oligomenorrhea, androgen excess, and DM2 had appeared. Patient 3 had prepubertal overgrowth in weight and height and was diagnosed with pseudo-acromegaly, menstrual irregularity, androgen excess, and impaired glucose tolerance at 14.3 years of age. Patient 4 had prepubertal overgrowth that evolved into pseudo-acromegaly, insulin resistance, secondary amenorrhea, and androgen excess at 15.6 years.

CONCLUSIONS

Intractable prepubertal obesity was recognized to culminate in early childhood pseudo-Cushing's syndrome or pseudo-acromegaly, which are manifestations of insulin-resistant hyperinsulinism, and to herald adolescent PCOS.