Androgen function

Therefore, both pituitary gonadotropins are required for optimal androgen function. LH acts on the Leydig cells to stimulate testosterone synthesis,... 

All classes of steroid hormones bind to specific cytoplasmic receptors in their respective target tissues, and are then translocated to the nucleus. For example, testosterone, a lipid-soluble substance, enters the cell and is enzymatically reduced to dihydrotestosterone by 5-a reductase. Dihydrotestosterone then becomes bound to a specific androgen receptor site located in the cytoplasm. This complex becomes activated and is then translocated to the nucleus, where it binds to the chromatin acceptor site consisting of DNA and nonhistone chromosomal proteins. This interaction results in the transcription of a specific messenger RNA that is then relocated to the cytoplasm and translated on the cytoplasmic ribosomes, resulting in the synthesis of a new protein that sponsors the androgenic functions (Figure 61.6). 

Steroid Hormones and Neurosteroids. Steroids (qv) can affect neuroendocrine function, stress responses, and behavioral sexual dimorphism (78,79) (see Steroids). Mineralocorticoid, glucocorticoid, androgen, estrogen, and progesterone receptors are localized in the brain and spinal cord. In addition to genomic actions, the neurosteroid can act more acutely to modulate the actions of other receptors or ion channels (80). Pregnenolone [145-13-17, ( ) dehydroepiandosterone [53-43-0] C H2 02 (319) are excitatory neurosteroids found in rat brain, independent of adrenal... 

Female sexual development and behaviour in mammals occurs by default and requires no ovarian secretion, and it is only in genetic males that the testis can secrete hormones which destroy this female pattern and superimpose that of the male. Sexual differentiation is not so well defined in fish, and larval exposure to both synthetic estrogens and androgens is widely used in aquaculture to produce monosex cultures. Endocrine disruption of sexual differentiation in fish may therefore reflect both the complexity and diversity of such processes between different species. Some care is required in use of the terms hermaphrodite and sex-reversal since a true hermaphrodite has both functional testes and ovaries and a sex-reversed fish is fully functional as its final sex—both produce the appropriate viable gametes. Such functional sex-reversal is not possible in mammals, but in some species of fish it is the normal developmental pattern. In most of the cases of hermaphroditism or sex-reversal reported in the non-scientific press, there is evidence only for a few ovarian follicles within a functional testis. This may be considered as feminisation or a form of intersex, and is very clearly endocrine disruption, but it is certainly neither sex-reversal nor hermaphroditism. In some cases the terms have even been used to infer induction of a single female characteristic such as production of yolk-protein by males. 

Therapeutic Function Androgen anabolic Chemical Name 17/J-Hydroxy-l 7-methylandrosta-1,4-dien-3-one Common Name Methandienone Structural Formula ... 

Therapeutic Function Androgen Chemicel Name 17-Hydroxyandrostan-3one Common Name Androstanolone... 

Sex steroid receptors are members of the steroid hormone receptor (SHR) family that ligand-dependently regulate functions of the sexual organs. Sex steroid receptors are the androgen receptor [1] (AR), the estrogen receptor a [2] and (3 [3] (ERa, ER 3), and the progesterone receptor [4] (PR). 

The adrenal cortex is functionally divided into three zones, the zona glomerulosa, fasciculata, and reticularis. Only the outermost zone, the zona glomerulosa, synthesizes aldosterone. The other zones are responsible for the generation of glucocorticoids and androgens. 

---