In regard to sex and reproduction the most important endocrine glands are pituitary gland and the gonads or sex glands –Testes in male and ovaries in female. The anterior pituitary gland secretes two gonadotropic hormones:
- Follicle stimulating Hormone (FSH) and
- Luteinizing hormone (LH).
They play major roles in the function of male and female function. During pregnancy placenta secretes human chorionic gonadotropic hormone that has the same property as LH. This hormone stimulates the interstitial cells of fetal testis and produces testosterone which promotes formation of male sexual organs. No testosterone is produced during childhood until the age of 10 to 13 years and lasts throughout life.
On stimulation by LH from anterior pituitary, Testosterone is produced by the interstitial cells of Leydig in the testes. FSH from anterior pituitary stimulates conversion of primary spermatocytes into secondary spermatocytes in the seminiferous tubules of testis.
However, for complete formation of spermatozoa testosterone is needed. Thus FSH iniates proliferative process of spermatogenesis and testosterone does final maturation of spermatozoa. Testosterone secretion, after puberty, causes the penis, scrotum and testis to enlarge until the age of 20. Testosterone causes secondary sex characteristics of the male.
In female, the anterior pituitary produces gonadotropic hormones FSH and LH which act on ovaries and produce estrogen and progesterone. During the reproductive years there is monthly rhythmic changes in the rate of section of female hormones and as menstrual cycle, is of 28 days.
Variation from 20 days to 36 days is taken as normal. At the age of about 8, the anterior pituitary begins secreting gonadotropic hormones, FSH & LH. These act on the ovaries. One of the follicles grows and ovulation takes place on the 14th day (counting from the first day of menstruation). During the growth of the follicle, estrogen is secreted. Following ovulation, the follicle develops into corpus luteum degenerates. The ovarian hormones, estrogen and progesterone decrease greatly and menstruation begins. Estrogen is responsible for secondary sex characters of the female. Progesterone is concerned with final preparation of uterus for pregnancy and the breasts for lactation.
Male’s capacity to be stimulated sexually shows a marked increase with the approach of adolescence. The frequencies of response to the point of orgasm reach the peak within three or four years after the onset of adolescence. Frequencies of sexual response in the male begin to decline after early thirties and drop steadily into old age.
Among females, the median frequencies of sexual activities remain constant from late teens into the fifties and sixties. In maximum incidences of sexual response are not approached until some time late twenties and thirties. Individuals who are physically exhausted or in ill health are not easily aroused sexually if aroused they may not be capable of effective action and may fail reach orgasm.
Estrogen occurs in equal amount in pre-adolescent female and male. But at the time of adolescence, estrogen increases abruptly in female. At the onset of adolescence there is no upsurge of sexual activities in the female. It is the male who suddenly becomes sexually active at adolescences.
Androgen are found in both males and females. Adrenal glands also produce androgens. In preadolescence, the androgen levels begin to rise more markedly in the male. There is sudden upsurge of sexual responsiveness and sexual activity are among males. In females, the levels of sexual response and sexual activity are much lower than the levels in the males.
When Testosterone is given to normal male, there is increase in frequency of morning erection, the frequency of erotic response to various stimuli and the frequency of masturbation. Testosterone is also used to increase the low rate of coitus which results in infertility. Sperm count also may increase by administration of Testosterone. However, indiscriminate use of testosterone may involve some danger like inhibited pituitary function and damage to the gonads. It may accelerate malignancy of prostate. Serum prostatic specific antigen estimation and a digital examination of prostate are mandatory prior to administration of Testosterone.
Both, androgen occur simultaneously in both the female and male bodies. There is a theory that estrogens counteract the effectiveness of androgens. Some clinicians use estrogen in effort to reduce the levels of responsiveness of males convicted as sex offenders. Though estrogens reduce the amount of androgens, the use of estrogens to lower sexual responses is debated. The adrenal cortex produces androgens and estrogens in both the males and females . In menopause when the estrogen level falls, the androgen produced by the adrenal glands is responsible for the growth of hair on the face females.
Similarly, When the level of androgen falls in elderly males, the estrogen from the adrenal glands dominate and produce enlargement of breasts in the males. Hormonal levels may affect the intensity and frequency of response, the frequency of sexual activity , but there is no relationship between the hormone and individual response to particular sort of psychological stimuli. There is no evidence to prove that the patterns of sexual behavior can be modified by hormone therapy.