Female reproductive cycle

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

Ovaries Estrogens, Progesterone Female reproductive cycle and sexual characteristics... 

The most frequent and prevalent use of the female hormones is in contraceptive preparations (see Hormonal Contraceptives ). The other primary indications for estrogen and progesterone are replacement of endogenous hormone production and subsequent resolution of symptoms related to hormonal deficiencies. This replacement can be especially important following menopause—that is, when the female reproductive cycle ceases and the associated cyclic production of the ovarian hormones ends. Specific clinical conditions that may be resolved by estrogen and progesterone are listed below. 

Hypogonadism. Estrogens, or a combination of estrogen and progesterone, may be used to treat abnormally low ovarian function. Appropriate use of these hormones induces the uterine changes and cyclic bleeding associated with the normal female reproductive cycle. 

The previous section highlighted the pivotal role that JH plays not only in pheromone gland differentiation, but also in its cyclic maturation in relation to the reproductive cycle. Most aspects of the female reproductive cycle in cockroaches... 

Figure 33.3. The female reproductive cycle. FSH, follicle stimulating hormone GnRH, gonadotropin-releasing hormone LH, luteinizing hormone. (Reproduced with permission from Thomas, M. J., and Thomas, J. A. Toxic responses of the reproductive system. In Klaassen, C. D. (Ed.). Casarett and Doull s Toxicology, 6th ed. McGraw-Hill, New York, 2001, pp. 673-709.

Q2 Explain the profile of gonadotropic hormones activity, i.e. luteinizing hormone (LH) and follicle-stimulating hormone (FSH), in a typical 28-day female reproductive cycle... 

The post ovulatory phase of the female reproductive cycle is the most constant in duration, lasting approximately from day 15 to 28 and represents the time between ovulation and the onset of the next menses. In the ovary, after ovulation, the LH stimulates the remnants of the mature follicle to develop into the corpus luteum, which secretes increasing quantities of progesterone and some estrogens. This is called the luteal phase of the ovarian cycle. Subsequent events in the ovary that ovulated an oocyte depend on whether or not the oocyte becomes fertilized. If the oocyte is not fertilized, the corpus luteum has a lifespan of only two weeks, after which it degenerates into a corpus albicans. As the levels of prog-... 

Very high amounts of selenium have resulted in decreased sperm counts, increased abnormal sperm, changes in the female reproductive cycle in rats, and changes in the menstrual cycle in monkeys. The relevance of the reproductive effects of selenium exposure in animals studied to potential reproductive effects in humans is not known. Selenium compounds have not been shown to cause birth defects in humans or in other mammals. 

Compounds that produce the same biological effects as progesterone are called progestins [1], These effects are mediated by the progesterone receptor (PR), which is an important drug target due to its prominent role in the female reproductive cycle. 

The utility of a set of long-term-acting regulators is evident the estrogens and progesterone that regulate the female reproductive cycle. In humans these hormones interact over a 4-week cycle to prepare the uterus for implantation of a fertilized ovum. 

Describe the actions of androgens on the female reproductive cycle. 

Schematic of the female reproductive cycle and the influences of exogenously administered hormones.

Brussaard, A.B., Devay, P., Leyting-Vermeulen, J.L. and Kits, K.S. (1999) Changes in properties and neurosteroid regulation of GABA-ergic synapses in the supraoptic nucleus during the mammalian female reproductive cycle. J. Physiol. 516 513-524. 

The metabolic profiles are analyzed for qualitative or quantitative changes in individual components which might correlate with the onset of disease processes or the female reproductive cycle. 

Forester, D. C., 1977, Comments on the female reproductive cycle and philopatry in Desmognathus ochrophaeus (Amphibia, Urodela, Plethodontidae), J. Herpetol., 11 311. 

Aldridge, R. D., 1979, Female reproductive cycles of the snakes Arizona elegans and Crotalus viridis, Herpetologica, 35 256. 

The systematic exclusion of women from studies on the pretext of added variability attributable to female reproductive cycles ... 

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