The pituitary gland is part of hypothalamic-pituitary–gonadal axis, which controls development, reproduction, and aging in humans and animals. In addition, the pituitary gland is regulated mainly by hormones and neurotransmitters released from the hypothalamus and by systemic hormones secreted by target glands. Aromatase P450, the enzyme responsible for the catabolization of aromatizable androgens to estrogens, is expressed in different parts of body, including the pituitary gland. Moreover, aromatase P450 is involved in sexual dimorphism where alteration in the level of aromatase can initiate a number of diseases in both genders. On the other hand, the direct actions of estrogens, mainly estradiol, are well known for stimulating prolactin release. Numerous studies have shown that changes in the levels of estrogens, among other factors, have been implicated in the genesis and development of prolactinoma. The pituitary gland can produce estradiol locally in several types of endocrine cells, and it is possible that aromatase could be responsible for the maintenance of the population of lactotroph cells and the modulation of the action of central or peripheral regulators. Aromatase overexpression due to inappropriate gene regulation has clinical effects such as the pathogenesis of prolactinomas. The present study reports on the synthesis of pituitary aromatase, its regulation by gonadal steroids, and the physiological roles of aromatase on pituitary endocrine cells. The involvement of aromatase in the pathogenesis of pituitary tumors, mainly prolactinomas, through the auto-paracrine production of estradiol is reviewed.

The aim of this study was to compare the external loads (i.e., displacement distances and velocities) of 10–11 years-old soccer players during Soccer-7 (i.e., seven-a-side), Soccer-8 (i.e., eight-a-side), and Soccer-11 (i.e., eleven-a-side) official matches. Male athletes (n = 133; age, 10.9 ± 0.8 years) were measured during official matches for total distance (TD), relative distance (Drel), maximal velocity (Vmax), acceleration (ACC), deceleration (DEC), and absolute and relative distance covered at different velocities. Data during matches were collected using a Global Positioning System unit. Greater TD was recorded during Soccer-11 compared to Soccer-7 and Soccer-8 (p < 0.01), and greater Drel during Soccer-11 compared to Soccer-8 (p < 0.05). Absolute ACC was greater during Soccer-11 compared to Soccer-7 (p < 0.01), although relative values for %ACC and %DEC were greater during Soccer-7 and Soccer-8 compared to Soccer-11 (p < 0.01). Globally, results show that Soccer-11 matches induce greater external loads compared to Soccer-7 and Soccer-8 matches. Current results may help coaches and soccer-related organizers to plan more suited soccer competitions for young players, with lower external loads.

El objetivo de este estudio fue analizar el valor de mercado (VM) de futbolistas profesionales de las 5 mejores ligas europeas de fútbol. Se analizó el efecto de las variables independientes sobre el VM de los futbolistas, mediante una ANOVA con un nivel de significación de p <0.01. Los futbolistas de la Premier League (PL) mostraron mayor VM en comparación con los de otras ligas. Los futbolistas extranjeros mostraron mayor VM en comparación con los futbolistas nacionales. Los futbolistas entre 21-30 años mostraron mayor VM en comparación con los 30 años. Los delanteros y centrocampistas, mostraron mayor VM en comparación con los porteros y los laterales. Los futbolistas que representaron a sus países en partidos internacionales mostraron mayor VM en comparación con los que no lo hicieron. Los futbolistas de formación juvenil en clubes de la PL y La Liga (LL) mostraron mayor VM en comparación con los futbolistas de otros clubes. En conclusión, factores intrínsecos y extrínsecos afectan el VM de los futbolistas. Los resultados de esta investigación pueden ser útiles para los directores deportivos en el proceso de selección de futbolistas profesionales. The objective of this study was analysed to the market value (MV) of professional soccer players from Top-5 European Soccer Leagues. An ANOVA analysed the effect of the independent variables on the MV of the soccer players, with p<0.01. Soccer players from the Premier League (PL) showed greater MV compared to other leagues. Foreign soccer players showed greater MV compared to national soccer players. Soccer players between 21-30 years showed greater MV compared to those 30 years. Forward and midfielders showed greater MV compared to goalkeepers and backs. Soccer players that represented their countries at international matches showed greater MV compared to those that did not. The soccer players with a youth background formation in their clubs in the Premier League and La Liga showed greater MV compared to soccer players coming from other clubs. In conclusion, intrinsic and extrinsic factors affect the MV of soccer players. Research results may be useful to the sport managers in the selection of professional soccer players. O objetivo deste estudo foi analisar o valor de mercado (VM) de jogadores de futebol profissional das 5 melhores ligas europeias de futebol. O efeito das variáveis independentes sobre a VM dos futebolistas foi analisado por meio de uma ANOVA com nível de significância de p <0,01. Os jogadores de futebol da Premier League (PL) apresentaram MV mais alto em comparação com os de outras ligas. Os jogadores de futebol estrangeiros apresentaram VM superior em comparação aos jogadores de futebol nacionais. Jogadores de futebol entre 21-30 anos apresentaram maior VM em comparação com aqueles com 30 anos. Os atacantes e meio-campistas mostraram maior VM em relação aos goleiros e laterais. Os jogadores de futebol que representaram seus países em jogos internacionais apresentaram maior MV em comparação com aqueles que não o fizeram. Jogadores de futebol em formação de jovens em clubes da PL e La Liga (LL) apresentaram maior VM em comparação com jogadores de futebol de outros clubes. Em conclusão, fatores intrínsecos e extrínsecos afetam a VM dos jogadores de futebol. Os resultados desta pesquisa podem ser úteis para dirigentes esportivos no processo de seleção de jogadores profissionais de futebol.

¿ES DETERMINANTE LA MODALIDAD DE COMPETICIÓN EN LA ACCIÓN DE REGATE EN FUTBOLISTAS SUB12?