The endocrinology of the reproductive years

Introduction. The relationship between reproductive physiology and reproductive behavior, a central theme in Professor Lorraine Dennerstein's career, is complex but presumably serves to optimize human reproduction. Aim. To review the endocrinology of the reproductive years and significant work by Professor Dennerstein relating that endocrinology with reproductive behavior. Methods/Main Outcome Measures. Published works of reproductive endocrinology by Professor Dennerstein. Results. An exquisitely controlled signaling loop between the ovaries and the hypothalamus and pituitary, in the brain represents the overlay of a dynamic neuroendocrine system on a responsive but ultimately decaying gonadal system. The most visible hallmark of this elegant interplay is the menstrual cycle, with coordinated hormone patterns directing the maturation and release of oocytes, and either supporting an early pregnancy or resetting the system for the next cycle. The recognition that these hormone patterns, or their perturbation, are related to psychosocial behaviors is reflected in Professor Dennerstein's earliest writings relating sex steroids to sexual behavior and menstrual cycles to affect, leading to studies describing psychological symptoms in the premenstrual syndrome (PMS). These were followed by clinical trials of progestins for PAIS with conflicting results, and an emerging interest in measuring endogenous hormones in that disorder. Her study of reproductive hormones across the menstrual cycle in women with PMS definitively refuted the theory that deficient progesterone secretion was the etiology of cyclic symptoms. Extension of that work demonstrated the cyclic pattern of sexual behavior, but the absence of a defined relationship with measured sex steroid patterns. Her interest In the effect of age on menstrual cyclicity evolved into her landmark work on the menopausal transition, the ultimate result of ovarian gamete depletion and absolute loss of spontaneous reproductive capacity Conclusion. Professor Dennerstein clearly demonstrated that reproductive behavior is related to reproductive Physiology, and can be measured and quantified.