Study on a pedigree with Leydig cell hypoplasia caused by novel mutation of luteinizing hormone receptor / 中华内分泌代谢杂志

Objective To investigate a Chinese pedigree suffering from Leydig cell hypoplasia ( LCH) based on clinical data and genetic diagnosis. Methods The patient was diagnosed by means of clinical data, hormone profiles, and human chorionic gonadotropin ( hCC) test. The luteinizing hormone/chorionic gonadotropin receptor(LHCGR) gene of the patient and family members was amplified and sequenced. Results The patient presented with male pseudohermaphroditism, low level of testosterone, which did not respond to hCG. Genetic analysis of the LHCGR revealed two novel mutations: a missense mutation located in exon 5, resulting in Ile replaced by Thr in the extracellular domain; and a splice site mutation in the 3' terminal of intron 6( IVS6-3 C→A). Proband's sister (46, XX) who lacked clinical manifestations showed the identical genotype with the patient. Conclusions A mutation in the consensus sequence of 3' splice site, in addition to a missense mutation (Ile 152Thr)in the extracellular ligand-binding domain is the cause of inactivation of the LHCGR gene in patient with Leydig cell hypoplasia.

Efectos de la leptina en el inicio de la pubertad en animales machos / Efeitos da leptina no inicio da puberdade em animais machos / Effects of the leptin in the onset of puberty in animal males

La leptina es una hormona de 16 KDa producida principalmente por el tejido adiposo, codificada por el gen ob y compuesta por 146 aminoácidos. Cumple sus funciones en la periferia del organismo en el eje hipotálamo – hipófisis – gónadas. En varias especies se ha estudiado el efecto de esta hormona en la reproducción; los cambios en su concentración y en su expresión podrían estar asociados con el inicio de la pubertad en diferentes especies animales y en los humanos. El rol de la leptina en la reproducción del macho ha sido estudiado especialmente en ratas y ratones, pero también se han realizado investigaciones en humanos y otras especies animales. En las células de Leydig, en los túbulos seminíferos, las espermatogonias y los espermatozoides, entre otros tipos de células, hay expresión de los receptores y el RNAm de receptores de leptina, lo que indica que puede haber una función importante de la leptina en los testículos. En general, se ha hallado un efecto inhibitorio de la testosterona con la secreción de leptina y viceversa, lo cual indica que la leptina puede regular la esteroidogénesis en el testículo. La leptina también puede actuar en células no diferenciadas del testículo para permitir su diferenciación en espermatocitos y puede asistir a la célula a través de toda su diferenciación y maduración hacia espermátides. A través de todos estos resultados obtenidos, se observa a la leptina como una importante hormona que puede estar involucrada en funciones vitales del eje neuroendocrino y reproductivo del macho.

The leptin is a 16 KDa hormone principally produced by the adipose tissue, codified by the ob gene and composed by 146 amino acids. This hormone carries out its functions at peripheral levels and in the hypothalamic– hypophysis – gonadal axis. In several species the effect of this hormone on reproduction and their concentration and expression changes might be associated with the onset of puberty in different animal species and in human beings. The role of leptin in male reproduction has been studied especially in rats, mice, human beings, and other animal species. Leptin receptor and mRNA expression has been found in Leydig cells, seminiferous tubules, spermatogonies, spermatozoa, among other cells, indicating that leptin could have an important role in testicular function. An inhibitory effect of testosterone on leptin secretion has been found and vice versa, which indicates that leptin can regulate testicular steroidogenesis. Leptin can also act in non differentiated cells of the testis, promoting spermiogenesis. Then, leptin appears to be an important hormone probably involved in vital functions of the male neuroendocrine and reproductive axis.

A leptina é um hormônio de 16 KDa produzida principalmente pelo tecido adiposo, codificada pelo gene ob e composta por 146 aminoácidos. Cumpre suas funções na periferia do organismo no eixo hipotálamo – hipófise – gônadas. Em varias espécies tem-se estudado o efeito deste hormônio na reprodução; as mudanças na concentração e em sua expressão poderiam estar associadas com o inicio da puberdade em diferentes espécies animais e em humanos. O papel da leptina na reprodução em machos tem sido estudado especialmente em ratas e ratos, porém também tem sido realizadas pesquisas em humanos e outras espécies animais. Nas células de Leydig, nos túbulos seminíferos, as espermatogônias e os espermatozóides, entre outros tipos de células, existe expressão dos receptores e o RNAm de receptores de leptina, o que indica que pode existir uma função importante da leptina nos testículos. Em geral, tem sido encontrado um efeito inibitório da testosterona com a secreção da leptina e vice versa, o qual indica que a leptina pode regular a esteroidogénese no testículo. A leptina também pode atuar nas células não diferenciadas do testículo para permitir sua diferenciação em espermatócitos e pode ajudar à célula a través de toda sua diferenciação e maturação até espermátides. A análise de todos estes resultados obtidos, permite considerar a leptina como um importante hormônio que pode estar envolvido em funções vitais do eixo neuroendócrino e reprodutivo do macho.

[125I] gonadotropin binding to the ovary of an Indian major carp, Catla catla, at different stages of reproductive cycle.

At different stages of the annual reproductive cycle of Catla catla, a major Indian carp, specific binding of gonadotropic hormone to the plasma membrane receptors was demonstrated. Maximum specific binding of [125I] Catla gonadotropic hormone was obtained at 30°C and pH 7·5 during 2 h of incubation. Catla gonadotropic hormone binding was saturable with high affinity. Competitive inhibition experiment showed that binding site was specifically occupied by piscine gonadotropic hormone, Catla gonadotropic hormone and murrel gonadotropic hormone, human chorionic gonadotropin was a weak competitor while bovine thyroid stimulating hormone, bovine prolactin and ovine follicle stimulating hormone had no effect. Scatchard analysis of Catla gonadotropic hormone binding to the plasma membrane preparation from the carp oocytes of different reproductive stages showed that the range of dissociation constant (Kd) varied from 0·78 to 0·97 × 10-10 M. However, maximum binding capacity (B-max) varied remarkably between the different stages of reproductive cycle, it was 6·11 ± 0·36 fmol/mg protein in the preparatory stage which increased to about three-fold in prespawning stage of reproductive cycle (17·0 ± 0·29 fmol/mg protein) and spawning (18·7 ± 0·17 fmol/mg protein) and lowest in postspawning stage of reproductive cycle (5·28 ± 0·28 fmol/mg protein). Fluctuation in the number of gonadotropic hormone binding site at different stages of annual reproductive cycle was found to be coincided well with the pattern of ovarian steroidogenesis in response to Catla gonadotropic hormone as determined by the formation of progesterone from pregnenolone.