Sexual characteristics, secondary

Turner s Syndrome. Turner s syndrome is a genetic disorder of females characterized by short stature, nonfunctioning ovaries, and failure to develop secondary sexual characteristics. Several clinical trials in the United States, Europe, and Japan have demonstrated that hGH can accelerate... 

Cells from tissues associated with primary and secondary sexual characteristics are under particular endocrine control. Sex hormones determinethe growth, differentiation, and proliferation of such cells. When a tumor develops in such tissues, it is sometimes hormone dependent and the use of anti hormones removes the impetus for the tumor s headlong growth. Many nonsteroidal compounds have estrogenic activity diethylstilbest-jrol (81) may be taken as an example. Certain more bulky an-... 

Therapeutic modalities for amenorrhea are targeted at restoring the normal menstrual cycle. The goals of treatment are to preserve bone density, prevent bone loss, and restore ovulation, thus improving fertility as desired. Amenorrhea resulting from conditions contributing to hypoestrogenism also may affect quality of life via the induction of hot flashes (premature ovarian failure), dyspareunia, and in prepubertal females, lack of secondary sexual characteristics and absence of menarche. 

The gonadotrophins are a family of hormones for which the gonads represent their primary target (Table 11.8). They directly and indirectly regulate reproductive function and, in some cases, the development of secondary sexual characteristics. Insufficient endogenous production of any... 

Estradiol is the most important of the estrogens. Like progesterone, it is synthesized by the ovaries and, during pregnancy, by the placenta as well. Estradiol controls the menstrual cycle, it promotes proliferation of the uterine mucosa, and is also responsible for the development of the female secondary sexual characteristics (breast, fat distribution, etc.). 

Testosterone is the most important of the male sexual steroids (androgens), it is synthesized in the Leydig intersitial cells of the testes, and controls the development and functioning of the male gonads, it also determines secondary sexual characteristics in men (muscles, hair, etc.). 

Replacement therapy - Replacement therapy in hypogonadism associated with a deficiency or absence of endogenous testosterone. Prior to puberty, androgen replacement therapy is needed for development of secondary sexual characteristics. Prolonged treatment is required to maintain sexual characteristics in these and other males who develop testosterone deficiency after puberty. Appropriate adrenal cortical and thyroid hormone replacement therapy are still necessary, however, and are of primary importance. 

Thus, these individuals have inappropriately low LH and FSH levels that do not respond to GnRH stimulation. Androgen replacement in these individuals usually restores secondary male sexual characteristics, such as libido and potency. 

Male and female sex hormones. Influence secondary sexual characteristics regulate female reproductive cycle. 

Male Hormones. The androgenic hormones produced in Ihe testes land adrenal gland t have a w idespread effect upon the development of secondary sexual characteristics (musculature, facial hair, larynx, etc. I. as well as upon the sexual organs and responses themselves. They also promote anabolism tu a marked degree by their effect upon nitrogen and calcium metabolism. The structure of testosterone is shown in the Tahle I. 

Steroid hormones have a variety of important functions, including regulation of carbohydrate and mineral metabolism and development of secondary sexual characteristics (Table 20.4). Steroids are often used in the treatment of diseases such as arthritis. Some athletes use steroids to promote muscle growth. 

Reproductive organs are the primary source of the steroid hormones that influence sexual and reproductive functions. In men, the testes produce testosterone and similar androgens that are responsible for spermatogenesis and the secondary sexual characteristics of adult males.7,26 In women, sexual maturation and reproductive function are governed by the production of estrogens and progestins from the ovaries.27 The release of male and female sex steroids is controlled by hormones from the hypothalamus and anterior pituitary.32 The control of male and female hormone activity and the pharmacologic implications of these hormones are discussed in Chapter 30. 

Androgens can produce changes in reproductive function and secondary sexual characteristics. In males, high levels of androgens act as negative feedback and lead to testicular atrophy and impaired sperm production. Infertility in males may result because of an... 

Failure of Ovarian Development. Occasionally, the ovaries fail to undergo normal development because of hypopituitarism or other disorders. Estrogens may be given at the time of puberty to encourage development of secondary sexual characteristics (e.g., breast development). 

ANDROGENIC EFFECTS Adrug s effects on the growth of the male reproductive tract and the development of male secondary sexual characteristics. 

Young fish that has not started its reproductive cycle with the absence of secondary sexual characteristics. Volume 1(14). 

Adolescent Beginning with the appearance of secondary sexual characteristics to achievement of full maturity (usually 12-18 years of age)... 

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