Steroid hormones types

The barbiturate type, the clofibrate type, the polycyclic hydrocarbon type, the steroid hormone type, and alcohol/acetone/isoniazid type. For example, the polycyclic hydrocarbon type act through a receptor. The barbiturate type increase liver blood flow. 

The barbiturate type the clofibrate type the polycyclic hydrocarbon type the steroid hormone type alcohol/acetone/isoniazid type. 

As RJ contains testosterone [24] and possesses steroid hormone-type activities [54—57], it was hypothesized that it may have beneficial effects on osteoporosis. In a recent study, both an ovariectomized rat model and a tissue culture model were used. The results of the study indicated that RJ was almost as effective as 17p-estradiol in preventing the development of bone loss induced by ovariectomy in rats. In tissue culture models, RJ increased calcium contents in femoral-diaphyseal and femoral-metaphyseal tissue cultures obtained from normal male rats however, in a mouse marrow culture model, it neither inhibited the parathyroid hormone (PTH)-induced calcium loss nor affected the formation of osteoclast-like cells induced by PTH. Therefore, these results suggested that RJ may prevent osteoporosis by enhancing intestinal calcium absorption, but not by directly antagonizing the action of PTH [60]. In a comparable study, it was investigated whether RJ and bee pollen reduce the bone loss due to osteoporosis in oophorectomized female rats model. It was concluded that RJ and bee pollen after a 12-week treatment decrease the bone loss due to osteoporosis, proposing that these results may contribute to the clinical practice [61]. 

The female of mammalian species secretes a series of steroid hormones characterized by an aromatic A ring and the lack of a side chain at the 17 position. These compounds serve as regulators in the reproductive processes of the species. The name (estrogens) comes from the fact that in some lower animals the elaboration of this type of compound is directly involved with the phe-... 

Adrenocortical hormone (Section 27.6) A steroid hormone secreted by the adrenal glands. There are two types of adrenocortical hormones mineralocorticoids and glucocorticoids. 

The ceUular source of the various ovarian steroids has been difficult to unravel, but a transfer of substrates between two cell types is involved. Theca cells are the source of androstenedione and testosterone. These are converted by the aromatase enzyme in granulosa cells to estrone and estradiol, respectively. Progesterone, a precursor for all steroid hormones, is produced and secreted by the corpus luteum as an end-product hormone because these cells do not contain the enzymes necessary to convert progesterone ro other steroid hormones (Figure 42-8). 

The complement of enzymes in a particular cell type allows for the production of a specific class of steroid hormone. 

Efforts to improve IUDs have led to the use of medicated devices. Two types of agents are generally used—contraceptive metals and steroid hormones. The metal device is exemplified by the CU-7, a polypropylene plastic device in the shape of the number 7. Copper is released by a combination of ionization and chelation from a copper wire wrapped around the vertical limb. This system is effective for up to 40 months. 

Adrenal cortex. The adrenal cortex forms the outer portion of the adrenal gland and accounts for 80 to 90% of the weight of the gland. It is the site of synthesis of many types of steroid hormones such as ... 

The signal is what starts everything off. Signals take a variety of forms, but for our purposes there are only two. The first type are signals that go into the cell, bind to internal receptors, and exert their effects. Steroid hormones, vitamin D, thyroid hormone, and retinoids are the only members of this class. All of the intracellular receptors ultimately activate the transcription of regulated genes. The common feature of signals that enter the cell is that they are all small lipophilic molecules that can cross the cell membrane. 

Steroid hormones are produced by only two tissue types, the adrenal cortex and the gonads. A summary of the steroid hormones is given in Table 4.2. Steroid hormones are synthesized from cholesterol (Figure 4.2). This sterol lipid may itself be synthesized within the steroidogenic cell or it may be delivered to the cell by circulating lipoprotein complexes such as low density lipoprotein (LDL) or high density lipoprotein (HDL). 

The follicular phase covers the development of the follicle, which involves an increase in its size due to an increase in follicular fluid, growth of the ovum (i.e. an increase in the contents of RNA and protein) and an increase in the number of cells that surround the ovum. These cells are of two types, the granulosa and the thecal cells. The role of these cells is to synthesise and secrete the steroid hormones oestrogens (mainly oestradiol). The precursor molecule for their synthesis is cholesterol. There is a division of labour between these cells the thecal cells convert cholesterol into the male sex hormones androstenedione and testosterone, which are released into the blood to be taken up by the granulosa cells where they are converted to the oestrogens (Figure 19.8). For details of pathways, see Appendix 19.1. 

Phase II reactions (conjugate formation). Type II reactions couple their substrates (bilirubin, steroid hormones, drugs, and products of phase I reactions) via ester or amide bonds to highly polar negatively charged molecules. The enzymes involved are transferases, and their products are known as conjugates. 

Many steroid hormones are regulated by this type of axis—e.g., thyroxin, cortisol, estradiol, progesterone, and testosterone. In the case of the glucocorticoids, the hypothalamus releases corticotropin-releasing hormone (CRH or corticoliberin, a peptide consisting of 41 amino acids), which in turn releases corticotropin (ACTFl, 39 AAs) in the pituitary gland. Corticotropin stimulates synthesis and release of the glandular steroid hormone cortisol in the adrenal cortex. 

Hormone antagonism Application of drugs that bind to and inhibit the steroid hormone receptors or different types of releasing hormone receptors... 

The cage-type peptide cyclophanes (7 and 8) exhibit discrimination toward steroid hormones, as effected by hydrophobic and n-n interactions. In addition, the chirality-based discrimination between a- and -estradiol as well as between D- and L-amino acids bearing an aromatic moiety is performed on the basis of their capacity of forming efficient hydrogen bonding with the host molecules in aqueous media [41, 43]. 

---