ABSTRACT
An experiment was conducted to investigate the central regulatory effects of estradiol on GnRH secretion leading up to the preovulatory LH surge in the ewe. Midluteal phase ewes were ovariectomized, treated with steroid implants to maintain luteal phase concentrations of progesterone and estradiol, and fitted with an apparatus for collection of hypophyseal portal blood. After simulated luteolysis (removal of progesterone implants), the ewes were allocated to one of three groups: estradiol withdrawn, estradiol maintained at a luteal phase level, or estradiol raised from a luteal phase level to a peak follicular phase level in two increments. The results demonstrated that during the interval between luteolysis and the preovulatory gonadotropin surge, estradiol exerts a dose-dependent suppression of GnRH secretion from the hypothalamus. This effect reflects a suppression of GnRH pulse size and occurs despite a stimulatory action of estradiol on GnRH pulse frequency. The suppressive effect of estradiol on GnRH secretion, however, was delayed relative to that on LH. We conclude that during the period leading up to the preovulatory surge in the ewe, estradiol acts centrally, reducing GnRH secretion by suppressing GnRH pulse size.
Subject(s)
Brain/physiology , Estradiol/pharmacology , Follicular Phase , Gonadotropin-Releasing Hormone/metabolism , Animals , Dose-Response Relationship, Drug , Female , Gonadotropin-Releasing Hormone/antagonists & inhibitors , Luteinizing Hormone/antagonists & inhibitors , Luteinizing Hormone/metabolism , Ovariectomy , Pulsatile Flow , SheepABSTRACT
A sympathetic, nonjudgmental approach may reveal sexual dissatisfactions to be the basis of vague complaints about health, opening the way to counseling, changes in drug regimens, and referrals that can greatly improve quality of life.
Subject(s)
Aged , Counseling , Sexual Dysfunction, Physiological , Coitus , Coronary Disease , Female , Humans , Male , Masturbation , Referral and Consultation , Sexually Transmitted DiseasesSubject(s)
Communication , Sexual Dysfunction, Physiological/etiology , Age Factors , Aged , Counseling , Female , Humans , Male , Sex Education , Sexual Dysfunction, Physiological/therapyABSTRACT
For the aged and aging of today, sex is not taboo. With the change in attitudes of younger people toward sex, the elderly are now seeking enrichment of their lives through continued sexual experience. Physicians with knowledge of the physiologic, endocrinologic, and sociologic aspects of sexuality can help to relieve the loneliness and isolation of older people by giving appropriate encouragement and counsel.
