Abnormalities of Secretion by the Ovaries

 Abnormalities of Secretion by the Ovaries

Hypogonadism. Less than normal secretion by the ovariescan result from poorly formed ovaries, lack of ovaries, or genetically abnormal ovaries that secrete the wrong hormones because of missing enzymes in the secretory cells. When ovaries are absent from birth or when they become nonfunctional before puberty, femaleeunuchism occurs. In this condition, the usual secondarysexual characteristics do not appear, and the sexual organs remain infantile. Especially characteristic of this condition is prolonged growth of the long bones because the epiphyses do not unite with the shafts as early as they do in a normal woman. Consequently, the female eunuch is essentially as tall as or perhaps even slightly taller than her male counterpart of similar genetic background.

When the ovaries of a fully developed woman are removed, the sexual organs regress to some extent so that the uterus becomes almost infantile in size, the vagina becomes smaller, and the vaginal epithelium becomes thin and easily damaged. The breasts atrophy and become pendulous, and the pubic hair becomes thinner. The same changes occur in women after menopause.

Irregularity  of      Menses,      and   Amenorrhea Caused      by Hypogonadism. As pointed out in the preceding dis-cussion of menopause, the quantity of estrogens pro-duced by the ovaries must rise above a critical value in order to cause rhythmical sexual cycles. Consequently, in hypogonadism or when the gonads are secreting small quantities of estrogens as a result of other factors, such as hypothyroidism, the ovarian cycle often does not occur normally. Instead, several months may elapse between menstrual periods, or menstruation may cease altogether (amenorrhea). Prolonged ovarian cycles are frequently associated with failure of ovulation, presum-ably because of insufficient secretion of LH at the time of the preovulatory surge of LH, which is necessary for ovulation.

Hypersecretion by the Ovaries. Extreme hypersecretion ofovarian hormones by the ovaries is a rare clinical entity, because excessive secretion of estrogens automatically decreases the production of gonadotropins by the pituitary, and this limits the production of ovarian hormones. Consequently, hypersecretion of feminizing hormones is usually recognized clinically only when a feminizing tumor develops.

A rare granulosa cell tumor can develop in an ovary, occurring more often after menopause than before. These tumors secrete large quantities of estrogens, which exert the usual estrogenic effects, including hypertrophy of the uterine endometrium and irregular bleeding from this endometrium. In fact, bleeding is often the first and only indication that such a tumor exists.

Comments

Post a Comment

Popular posts from this blog

Use of Proteins for Energy

Image
  Use of Proteins for Energy Once the cells are filled to their limits with stored protein, any additional amino acids in the body fluids are degraded and used for energy or are stored mainly as fat or secondarily as glycogen. This degradation occurs almost entirely in the liver, and it begins with deamina-tion,  which is explained in the following section. Deamination.  Deamination means removal of the aminogroups from the amino acids. This occurs mainly by transamination, which means transfer of the amino group to some acceptor substance, which is the reverse of the transamination explained earlier in relation to the synthesis of amino acids. The greatest amount of deamination occurs by the following transamination schema: Note from this schema that the amino group from the amino acid is transferred to a-ketoglutaric acid, which then becomes glutamic acid. The glutamic acid can then transfer the amino group to still other substances or release it in the form of ammonia ...
Read more

Cretinism

  Cretinism Cretinism is caused by extreme hypothyroidism during fetal life, infancy, or childhood. This condition is char-acterized especially by failure of body growth and by mental retardation. It results from congenital lack of a thyroid gland ( congenital cretinism ), from failure of the thyroid gland to produce thyroid hormone because of a genetic defect of the gland, or from iodine lack in the diet ( endemic cretinism ). The severity of endemic cre-tinism varies greatly, depending on the amount of iodine in the diet, and whole populaces of an endemic geo-graphic iodine-deficient soil area have been known to have cretinoid tendencies. A neonate without a thyroid gland may have normal appearance and function because it was supplied with some (but usually not enough) thyroid hormone by the mother while in utero, but a few weeks after birth, the neonate’s movements become sluggish and both physi-cal and mental growth begin to be greatly retarded. Treatment of the neonate with cr...
Read more

Menopause

Image
  Menopause At age 40 to 50 years, the sexual cycle usually becomes irregular, and ovulation often fails to occur.After a few  months to a few years, the cycle ceases altogether, as shown in Figure 81–10.   The period during which the cycle ceases and the female sex hormones diminish to almost none is called  menopause. The cause of menopause is “burning out” of the ovaries. Throughout a woman’s reproductive life, about 400 of the primordial follicles grow into mature follicles and ovulate, and hundreds of thousands of ova degenerate. At about age 45 years, only a few primor-dial follicles remain to be stimulated by FSH and LH, and, as shown in Figure 81–10, the production of estrogens by the ovaries decreases as the number of primordial follicles approaches zero. When estrogen production falls below a critical value, the estrogens can no longer inhibit the production of the gonadotropins FSH and LH. Instead, as shown in Figure 81–9, the gonadotropins FSH and LH (mai...
Read more