The aim of this study was to investigate the effects of long-term stay of Japanese quail in simulated microgravity on some sexual features of males. As a model for simulating microgravity exposure of birds in laboratory conditions was used hypodynamia. The mean left testis weight in males reared under hypodynamia from day 3 up to 180 days of age was lower than that of control (P<0.05), but the ...

In many taxa, the left and right testes often differ in size. The compensation hypothesis states that one testis of the pair serves as a 'back-up' for any reduced function in the other and provides a mechanism to explain intraspecific variation in degree and direction of gonad asymmetry. Although testis asymmetry is common in birds, evidence for natural testis compensation is unknown. Using a n...

Background: Hops Plant (Humulus lupulus L.) plants is very beneficial has many industrial and medical applications. hops has protein, amino acids, lipids, fatty acids, sugars such as glucose and fructose, pectin, salts, wax and estrogenic compounds. So the aim of this study was to evaluate the effect of hops extracts on hormone levels and sex cells in adult mice. Materials and Methods: 40 adult...

Macroscopic and microscopic study of the testis after vasectomy and ligation of vasefferentia of testis in adult male albino rats. a b c d Original Article Vasectomy Fertility Adult male albino rats Sexual potency The present study is done to reassess the effects of ligation of excurrent duct system of testis at different levels in adult male albino rats and to study the long term effects of va...

Comparative analyses suggest that a variety of factors influence the evolution of sexual dimorphism in birds. We analyzed the relative importance of social mating system and sperm competition to sexual differences in plumage and body size (mass and tail and wing length) of more than 1,000 species of birds from throughout the world. In these analyses we controlled for phylogeny and a variety of ...

In order to examine the relation between intra-sexual fightings and sexual maturity, observations of tooth scars on the head of sperm whales (Physeter catodon) were made collected in South Pacific Oceans during 10 to 18 March 1979 on the Nisshin maru No. 3. Tooth scars on the head were observed on 48 males based on the following four relative stages; none, indistinct, distinct and heavy. Distin...

It has been an indisputable fact that the constitu-tive sex in mammalian fetal development is female. Furthermore, a functioning ovary is not required for the female phenotype, whereas a testis is mandatory for male development. More than 50 years after Jost performed experiments in rabbit embryos in which castration was followed by testis engraftment, his observations remain a beacon of clarit...

The aim of this study was to investigate the effects of ethanolic extract of Pueraria tuberosa (PT) on sexual behaviour and androgenic activity. Male albino rats were divided into four groups of six animals each: control group 1 (2% acacia solution), PT-treated group 2 (50 mg/Kg), PT-treated group 3 (100 mg/Kg), and PT-treated group 4 (150 mg/Kg). Sexual behavior of male rats in the presence of...

Mammalian oocytes and spermatozoa derive from fetal cells shared by the sexes. These primordial germ cells (PGCs) migrate to the developing somatic gonad, giving rise to oocytes or spermatozoa. These opposing sexual fates are determined not by the PGCs' own sex chromosome constitution (XX or XY), but by the sexual identity of the fetal gonad that they enter. We asked whether PGCs undergo a deve...

Studies in invertebrate taxa suggest that postcopulatory sexual selection is an important factor in genital evolution. However, despite wide interspecific variation in genital morphology, evidence for an influence of sexual selection on mammalian genitalia is equivocal. Here I conduct phylogenetically controlled comparative analyses across four mammalian orders to assess how one aspect of this ...