The hypothalamic-pituitary-gonadal axis plays a central role in the regulation of gamete maturation, sex steroid production and the stimulation of reproductive behaviours in vertebrates. In seasonal breeders, the timely activation and deactivation of this control system is important to ensure successful reproduction: this process is not well understood in species which breed irregularly. Males ...

elegance. Although much more precision could be added to the system, it is doubtful whether the purely qualitative aspects could ever be removed. The shape of the generating curve, for example, is generally irregular enough to greatly hinder mathematical description. Furthermore, the complete generating curve, as a closed curve, can rarely be seen, and thus its position relative to the axis of ...

1. In vertebrates, reproduction is primarily controlled by the HPG axis and, the structure of this endocrine pathway is highly conserved in jawed vertebrates (gnathostoma). The hypothalamic neuroendocrine system regulates synthesis and release of the gonadotropins, follicle-stimulating-hormone (FSH) and LH, from the pituitary, which in turn stimulate gonadal development, in particular via the i...

Reproductive function involves an interaction of three regulatory levels: hypothalamus, pituitary, and gonad. The primary drive upon this system comes from hypothalamic gonadotropin-releasing hormone (GnRH) neurosecretory cells, which receive afferent inputs from other neurotransmitter systems in the central nervous system to result in the proper coordination of reproduction and the environment...

In order to reproduce successfully, animals must integrate multiple environmental cues to synchronize breeding with favorable conditions. In temperate, seasonally breeding rodents, photoperiod acts as the primary seasonal cue. Long days are associated with reproductive development and maturation of the gonads whereas short days induce gonadal regression. The neuropeptide kisspeptin has potent s...

Puberty is a complex process that culminates in the acquisition of psychophysical maturity and reproductive capacity. This elaborate fascinating marks end childhood. Behind it lies complex, genetically mediated neuroendocrine mechanism through which gonads are activated thanks to fine balance between central inhibitory stimulating neuromodulators hormones with both peripheral action. The onset ...

Diabetes is a metabolic disorder which affects whole body systems including reproductive system. Diabetes is also a contributing factor to infertility. Metformin is one of the most common drugs to control hyperglycemia. In this study, 36 adult Sprague-Dawley female rats (170-210 g) were divided into 3 groups (control, diabetic and diabetic-treated by metformin). In second and third groups, diab...