Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 23

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  neurohormony
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Kisspeptin is a newly-discovered neurohormone, which is secreted from the hypothalamus. Initially it was thought that kisspeptin takes part in metastasis suppression. However, nowadays it is known that this hormone plays an essential role in the modulation of the hypothalamus-pituitary-gonadal axis. It has been demonstrated that mutation in the gene encoding kisspeptin’s receptor causes hypogonadotrophic hypogonadism and infertility in animals and humans. It is well established that kisspeptin may directly stimulate hypothalamic neurons. In addition, this neurohormone directly affects the pituitary and gonads. In the current review the authors sum up all information about different ways of direct and indirect effects of kisspeptin on reproductive processes and also present a novel insight into the mechanism responsible for the feedback loop of estrogen and androgen in mammals.
The current data on the occurrence, synthesis, liberation and specific receptors of cholecistokinine in tissues and body fluids have been presented. The potential of known competive antagonists of cholecistokinine in relation to the role it plays in animals and man was also discussed.
The structure and function of the epidural cavernous sinus and carotid rete (epidural cavernous sinuscarotid rete), located in the sella turcica of the sphenoid bone, named by physiologists the perihypophyseal vascular complex was described. New new facts questioning the role of this vascular complex in the regulation of brain temperature was presented. However, its role in the recently discovered retrograde transfer of neurohormones (GnRH, oxytocin, β-endorphin, dopamine) from venous blood outflowing from the brain and hypophysis to the arterial blood supplying the brain and hypophysis as well as dependence of this transfer on the stage of reproductive processes in females was shown. Moreover, the participation of perihypophyseal vascular complex in the recently discovered destination transfer of male feromone from venous nasal blood to the arterial blood supplying the brain and hypophysis was presented. It was concluded that the perihypophyseal vascular complex plays a significant role in retrograde transfer of brain and hypophyseal neuropeptides and in the destination transfer of feromenes from the nasal cavity to the brain and hypophysis by humoral pathway. Both these processes participate in the regulation of reproduction in females.
In the last quarter century, new neurobiological functions of oxytocin (OXY) have been documented. Apart from the important hormonal roles of OXY in the reproductive system (parturition, lactation), it also acts as a neurotransmitter and/or neuromodulator via specific oxytocin receptors(OXYR) in different central nervous structures and peripheral tissues. A high density of OXYR in nervous structures has been confirmed in the amygdala, hypothalamus, hippocampus, nucleus accumbens, striatum, septum, spinal cord, and prefrontal cerebral cortex, which are responsible for states of tension and high emotional intensity, as well as in the adrenal gland – the terminal segment of the hypothalamic-hypophyseal-adrenal axis. OXY is a particularly important neurohormone in the physiopathology of social behaviours and mental states, such as fear, anxiety, aggression, depression, schizophrenia, and autism in humans. The anti-stress and anxiolytic effects of OXY are based mainly on its antagonistic influence on Glu and DA, and on its stimulating influence on the GABAergic central inhibitory system. In addition, OXY inhibits cortisol and CA (stress hormones) release from the cortex and medulla of the adrenal gland during stress.
Mammalian reproduction is the most energy-consuming biological process. However, chronic dietary energy deficits, as well as energy surpluses can impair reproductive capacity, including the ability to produce viable gametes, and interrupt pregnancy or lactation. Thus, there is no doubt that the mechanisms controlling energy balance are integrated with those that control reproduction. There is functional evidence for a crucial connection between those mechanisms in the gonadotropin-releasing hormone (GnRH) cells of the hypothalamus, which are part of the hypothalamo-pituitary-gonadal (HPG) axis. Recent research has shown that the multiple hypothalamic peptidergic systems responsible for the homeostatic control of energy balance are involved in signaling to GnRH neurons. This group includes neuropeptyd Y (NPY), melanin-concentrating hormone (MCH), proopiomelanocortin (POMC), as well as periphery factors, such as leptin, ghrelin and insulin. However, the discovery of kisspeptin and gonadotropin-inhibitory hormone (GnIH) sheds a new light on mechanisms by which reproductive activity is regulated, also in the context of diurnal and annual photoperiod-driven cycles of mammals’ energy requirements. Thus, it seems clear that those two peptides are very important in linking the processes of energy balance maintenance and reproduction.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 2 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.