FIND ARTICLE

NEUROENDOCRINE FUNCTION OF SKIN

The skin constitutes the metabolically active biological barrier separating the internal milieu of mammalian organism and the external environment. The skin is continuously exposed to hostile environmental factors, therefore the anatomic localization determines its many functions. Both, the central endocrine system and the cutaneous endocrine system control and integrate the functions. All factors controlling the activity of the hypothalamus-pituitary-target organ axis are expressed in the skin.

SKIN AND ITS FUNCTION IN STEROID HORMONE SYNTHESIS

The skin is a complex organ of human body, which plays an essential role, providing physical barrier against mechanical, chemical and biological factors and, through its pigments produced in melanocytes, provides defense system against UV radiation, and reduces the risk of UV-induced DNA damage in human epidermis. The skin is composed of three layers: epidermis and its derivatives, dermis, and hypodermis. The function of the skin, especially hair growth and activity of sebaceous glands, is regulated by sex steroids, and skin is the target organ for these hormones.

ESTROGENS IN MALE REPRODUCTIVE SYSTEM

The presence of estrogens in the male gonad is now well documented, however the role of the hormones in regulation of function of male reproductive system is not fully understood. The using of molecular biology methods provided evidence that the cells of male reproductive system organs are able to produce estrogens via aromatization of androgens and are estrogen target. The cytochrome P450 aromatase and both isoform of estrogen receptors are expressed not only in Leydig and Sertoli cells, but also in germ cells, spermatozoa, the cells of epithelium in the efferent ductules and epididymis.

THE INFLUENCE OF XENOESTROGENS ON MALE REPRODUCTIVE SYSTEM

There are many hypotheses on the increase of male infertility. The phenomenon is believed to be connected with the presence of substances with hormonal activity – xenoestrogens in human environ- ment. The substances are divided into two groups: man made substances and components occurring naturally – phytoestrogens. Steroids influence not only male and female reproductive systems but also development and function of another tissue. Therefore, this is very important to list of substances with hormonal activity, their potency of acting, the way of expositions.

Developmental and gonadal dysfunction caused by the malfunction of hormones influencing the development of male reproductive system

The development of male reproductive system induced and controlled by hormones produced in the testis differentiation . Androgen insensitivity caused by a mutation of the AR receptor , or the lack of activity of 5a - reductase which convert T to DHT , are the cause of developmental abnormalities and often the cause of male infertility . Similar effects causes no effects of estrogen , resulting from mutations in the cytochrome P450 aromatase gene and a team of resistance to these hormones , caused by mutation of estrogen receptors .

Hormones epididymis

Sperm after leaving the nucleus are not yet fully mature. In the epididymis undergo a series of morphological changes , biochemical and functional . Their effect is to achieve the ability of sperm to the progressive movement , survival in male and female genital tract , capacitation , acrosome reaction and carrying out fertilization of the ovum . The specific environment in which the spermatozoa mature and are maintained viability , is produced by the epithelial cells lining the duct of the epididymis .

The Editorial Board
Andrzej Łukaszyk - przewodniczący, Zofia Bielańska-Osuchowska, Szczepan Biliński, Mieczysław Chorąży, Aleksander Koj, Włodzimierz Korochoda, Leszek Kuźnicki, Aleksandra Stojałowska, Lech Wojtczak

Editorial address:
Katedra i Zakład Histologii i Embriologii Uniwersytetu Medycznego w Poznaniu, ul. Święcickiego 6, 60-781 Poznań, tel. +48 61 8546453, fax. +48 61 8546440, email: mnowicki@ump.edu.pl

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