ter "The Development of In Vitro Fertilization from Laboratory Animals to Humans," by M.C. Chang, the pioneer in the field, is very interesting from both its historical standpoint and the fact that it is a fine dissertation on comparative reproductive physiology. It points out pertinent applications of animal and laboratory work to human work. The chapter by Lopata and Wood entitled "In Vitro F...

Since the discovery of gonadotropin-releasing hormone (GnRH) in mammals at the beginning of the 1970s, it was generally accepted that GnRH is the only hypothalamic neuropeptide regulating gonadotropin release in mammals and other vertebrates. In 2000, however, gonadotropin-inhibitory hormone (GnIH), a novel hypothalamic neuropeptide that actively inhibits gonadotropin release, was discovered in...

Cheaters are a threat to every society and therefore societies have established rules to punish these individuals in order to stabilize their social system. Recent models and observations suggest that enforcement of reproductive altruism (policing) in hymenopteran insect societies is a major force in maintaining high levels of cooperation. In order to be able to enforce altruism, reproductive c...

How chronic exposure to aquatic pollution affects reproductive traits was assessed in nesting wild-caught plainfin midshipman Porichthys notatus in areas with low and high contaminant exposure on Vancouver Island, British Columbia. Males in high-exposure areas had a greater degree of testicular asymmetry, sperm with shorter heads and fewer live eggs in their nests. The results of this study pro...

Life-history theory predicts that stress responses should be muted to maximize reproductive fitness. Yet, the relationship between stress and reproduction for semelparous salmon is unusual because successfully spawning individuals have elevated plasma cortisol levels. To tease apart the effects of high baseline cortisol levels and stress-induced elevation of cortisol titers, we determined how v...

Vertebrates displaying seasonal shifts in reproductive behavior provide the opportunity to investigate bidirectional plasticity in sensory function. The midshipman teleost fish exhibits steroid-dependent plasticity in frequency encoding by eighth nerve auditory afferents. In this study, evoked potentials were recorded in vivo from the saccule, the main auditory division of the inner ear of most...

There has been little focus on men's reproductive health (RH) in China. This descriptive study conducted in Yiling District, Yichang, China, surveyed male knowledge of sexual physiology and RH to assess levels of knowledge, attitudes and practices (KAPs) regarding prevention of sexually transmitted diseases (STDs). A total of 3933 men, aged 18-59 years (mean, 40.3 years), were recruited by clus...

Timing of breeding to an optimal season is a requirement for a successful reproductive outcome in seasonally breeding species. Photoperiodic signals are capable of modifying the reproductive behaviour and reproductive systems in several vertebrate species. The cichlid fish Cichlasoma dimerus shows highly organized breeding activities and different social status. The aim of this study is to test...