Endocrine Abstracts

In mammals, the preovulatory LH surge is thought to be triggered by enhanced release of GnRH into the hypothalamic–pituitary portal blood vessels. Recently, we discovered that the medial basal hypothalamus (MBH) of rhesus macaques (Macaca mulatta) contains two distinct populations of GnRH-producing neurones. One of these populations expresses the traditional mammalian form of GnRH (i.e. GnRH-I) while the other expresses a more conserved vertebrate form of GnRH (i.e...

Amyloid beta (Aβ) plaques represent one of the classic hallmarks of Alzheimer’s disease (AD) pathology in the brain. In rhesus macaques, these plaques start becoming prominent when the animals are 20+ years old, although the underlying cause(s) are unclear. In the present study, our goal was to test the hypothesis that exposure to a Western-style, high-fat, high-sugar diet (WSD) and/or loss of ovarian steroids would advance the development of this histological marker...

In humans and rhesus monkeys (Macaca mulatta) the zona reticularis of the adrenal gland produces large amounts of dehydoepiandrosterone (DHEA) and its sulfated form, DHEAS. The circulating levels of these steroids are particularly high during early adulthood, and they then decline gradually during aging, especially in females. To help elucidate the physiological function of this steroidal loss we examined the 24-hour plasma profiles of DHEAS in female rhesus monkeys, us...

Age-related cognitive decline in postmenopausal women is thought to be partially related to the loss of sex steroids. Like women, old female rhesus monkeys (Macaca mulatta) undergo menopause and show an associated decline in circulating estradiol levels. Similarly, they show an age-related decline in the release of dehydroepiandrosterone (DHEA) from their adrenal glands. Because DHEA acts as a substrate for estradiol synthesis in the brain, it is plausible that DHEA sup...