The present study was conducted to investigate the influence of hemicastration and age at hemicastration on the subsequent testicular development of male rabbits through sexual maturity. Thirty New Zealand white rabbits were left intact or were hemicastrated on Day 35, 49, 77, or 105 postconception. Beginning at 7 mo of age, ejaculates were collected every other day for 1 mo, and the last ten e...

Genes expressed in testes are critical to male reproductive success, affecting spermatogenesis, sperm competition, and sperm-egg interaction. Comparing the evolution of testis proteins at different taxonomic levels can reveal which genes and functional classes are targets of natural and sexual selection and whether the same genes are targets among taxa. Here we examine the evolution of testis-e...

In the course of trapping English Sparrows (Passer domesticus) in the Los Angeles area in the summer of 1952, three juvenal males with enlarged testes were taken. Histologic examination of the gonads of these individuals showed that all three were in breeding condition. In the descriptions of these juveniles, the following criteria of sexual maturity were used: 1. Bill color. The bill of Passer...

Experiments were conducted to address recent reports of precocial testis development or testicular hypertrophy induced by the anti-thyroid agent 6-N-propyl-2-thiouracil (PTU) in domestic fowl and rodents. In three experiments, PTU was administered to male turkeys during different stages of development. The PTU was given in the feed at a concentration of either 0.1 or 0.5% and effects on thyroid...

In male Tokara (Japanese native) goats, testis development and the onset of puberty were studied histologically and observing sexual behaviour. Testes weight increased from 36+/-5.4 (S.E.) g (n=5) at 3 months of age to 126+/-6.3 g (n=6) at 12 months. The degree of the testis development differed among kids at 3 months of age and only one of four had produced spermatozoa in the testis. Large num...

In Drosophila melanogaster, there is an excess of genes duplicated by retroposition from the X chromosome to the autosomes. Most of those retrogenes that originated on the X chromosome have testis expression pattern. These observations could be explained by natural selection favoring genes that avoided spermatogenesis X inactivation or by sexual antagonistic effects favoring the fixation of mal...

BACKGROUND In mammals, testis development is initiated in the embryo in response to the expression of the sex determining gene, Sry, in Sertoli cell precursors. Subsequently, Sertoli cells are thought to play a central role in male-specific cell interactions, including those that occur during spermatogenesis. However, the molecular nature of these interactions is poorly understood. Desert hedge...

Transgenic mice expressing high levels of the BclxL or Bcl2 proteins in the male germinal cells show a highly abnormal adult spermatogenesis accompanied by sterility. This appears to result from the prevention of an early and massive wave of apoptosis in the testis, which occurs among germinal cells during the first round of spermatogenesis. In contrast, sporadic apoptosis among spermatogonia, ...

The met protooncogene encodes the hepatocyte growth factor receptor (HGFR, c-met). C-met, a tyrosine kinase receptor protein, is widely expressed in different cell types including the male reproductive tract. As we recently demonstrated, both c-met messenger RNA and protein are expressed in prebuberal rat testis. The aim of this work was to detect the expression of c-met during postnatal testis...

In mammals, exposure to antiandrogenic chemicals during sexual differentiation can produce malformations of the reproductive tract. Perinatal administration of AR antagonists like vinclozolin and procymidone or chemicals like di(2-ethylhexyl) phthalate (DEHP) that inhibit fetal testicular testosterone production demasculinize the males such that they display reduced anogenital distance (AGD), r...