N-Terminal Prolactin-Derived Fragments, Vasoinhibins, Are Proapoptoptic and Antiproliferative in the Anterior Pituitary

The anterior pituitary is under a constant cell turnover modulated by gonadal steroids. In the rat, an increase in the rate of apoptosis occurs at proestrus whereas a peak of proliferation takes place at estrus. At proestrus, concomitant with the maximum rate of apoptosis, a peak in circulating levels of prolactin is observed. Prolactin can be cleaved to different N-terminal fragments, vasoinhibins, which are proapoptotic and antiproliferative factors for endothelial cells. It was reported that a 16 kDa vasoinhibin is produced in the rat anterior pituitary by cathepsin D. In the present study we investigated the anterior pituitary production of N-terminal prolactin-derived fragments along the estrous cycle and the involvement of estrogens in this process. In addition, we studied the effects of a recombinant vasoinhibin, 16 kDa prolactin, on anterior pituitary apoptosis and proliferation. We observed by Western Blot that N-terminal prolactin-derived fragments production in the anterior pituitary was higher at proestrus with respect to diestrus and that the content and release of these prolactin forms from anterior pituitary cells in culture were increased by estradiol. A recombinant preparation of 16 kDa prolactin induced apoptosis (determined by TUNEL assay and flow cytometry) of cultured anterior pituitary cells and lactotropes from ovariectomized rats only in the presence of estradiol, as previously reported for other proapoptotic factors in the anterior pituitary. In addition, 16 kDa prolactin decreased forskolin-induced proliferation (evaluated by BrdU incorporation) of rat total anterior pituitary cells and lactotropes in culture and decreased the proportion of cells in S-phase of the cell cycle (determined by flow cytometry). In conclusion, our study indicates that the anterior pituitary production of 16 kDa prolactin is variable along the estrous cycle and increased by estrogens. The antiproliferative and estradiol-dependent proapoptotic actions of this vasoinhibin may be involved in the control of anterior pituitary cell renewal

Does Living in a Fatherless Household Compromise Educational Success? A Comparative Study of Cognitive and Non-cognitive Skills

This study addresses the relationship between various family forms and the level of cognitive and non-cognitive skills among 15- to 16-year-old students. We measure cognitive skills using standardized scores in mathematics; non-cognitive abilities are captured by a composite measure of internal locus of control related to mathematics. A particular focus lies on father absence although we also examine the role played by co-residence with siblings and grandparents. We use cross-nationally comparable data on students participating in the Programme for International Student Assessment's release for 2012. By mapping inequalities by family forms across 33 developed countries, this study provides robust cross-country comparable evidence on the relationship of household structure with both cognitive and non-cognitive skills. The study produces three key results: first, the absence of fathers from the household as well as co-residence with grandparents is associated with adverse outcomes for children in virtually all developed countries. Second, this is generally true in terms of both cognitive and non-cognitive skills, although the disadvantage connected to both family forms is notably stronger in the former than in the latter domain. Finally, there is marked cross-national diversity in the effects associated with the presence in the household of siblings and especially grandparents which furthermore differs across the two outcomes considered

Prolactinomas in Men

Prolactinomas in men have several peculiar features that distinguish them from female PRL-secreting tumors. They occur less frequently in the male gender but are usually larger, more frequently invasive, and more often aggressive than in women. Significantly higher prolactin concentrations are also observed in men as compared to women, especially in the case of macroprolactinoma. Sex differences in tumor behavior largely explain such characteristics, rather than the longer delay in making the diagnosis in men. The reasons for a more aggressive course of prolactinomas in men remain poorly understood, and some hypotheses will be discussed in this chapter. Striking differences also exist in the clinical presentation of prolactinoma. Most women will present with oligomenorrhea, infertility, and/or galactorrhea, while more than half of men initially complain from symptoms of mass effects. Male hypogonadism is often present but neglected, and the male reproductive axis appears to be less sensitive to hyperprolactinemia than the female one. Nonetheless, diagnosis of prolactinoma in men should rely on the same criteria as in women, and a similar therapeutic strategy should be used. Medical management with dopamine agonists (DA) is effective and should always be considered as the first-line therapy, also in men bearing very large and compressive tumors. Transsphenoidal surgery is indicated in patients who are either intolerant or resistant to dopamine agonists or who elect to undergo potential curative surgery. However, most male patients with a macroprolactinoma will require medical treatment to control prolactin hypersecretion after surger