The objective of the present study was to verify the seasonal luteal activity of racehorses in training in Japan from March to August. We allocated 102 horses into a luteal activity group and non-luteal activity group. The luteal activity group included horses with serum progesterone levels that were consistently >1 ng/ml and changed by ± 1 ng/ml. In contrast, the progesterone levels of the non...

OBJECTIVE To investigate the in vitro effect of endothelin-1 (ET-1) on the steroid production (progesterone [P] and estradiol [E2]) by cultured human granulosa cells (GCs) during aging. MATERIAL AND METHODS Human ovarian GCs and granulosa-luteal cells (GLCs) were isolated from ovaries of female patients (young and premenopausal) undergoing surgery for non-ovarian benign gynecological conditio...

The results of this study, carried out with purified rat Leydig cells, indicate that there are no major differences in the stimulating effects of lutropin (LH) and luliberin (LHRH) agonists on steroidogenesis via mechanisms that are dependent on Ca2+. This was demonstrated by using inhibitors of calmodulin and the lipoxygenase pathways of arachidonic acid metabolism. All three calmodulin inhibi...

BACKGROUND Bovine luteal parenchymal cells express class II major histocompatibility complex (MHC) molecules and stimulate class II MHC-dependent activation of T cells in vitro. The ability of a class II MHC-expressing cell type to elicit a response from T cells in vivo is also dependent on expression of costimulatory molecules by the antigen presenting cell and delivery of a costimulatory sign...

BACKGROUND Menstrual cycle-related symptoms are an important health issue for many women, and some may affect cardiac autonomic regulation. In the present study, we evaluated the cardiovascular and physiological stress response to 12-h short-term fasting in the menstrual phases of healthy young women. METHODS We performed a randomized crossover study. Subjects were seven female university stu...

A bstract. The pattern of episodic gonadotropin release was studied in 15 normal female volunteers during the luteal phase ofthe menstrual cycle with 24 h ofblood sampling for follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels at 10-min intervals. Six subjects (two in the early, two in the mid-, and two in the late luteal phase) also had each of these specimens processed for...

This study assessed whether premenstrual symptomatology and/or sleep characteristics explain increased luteal phase psychophysiological reactivity to laboratory stressors. We hypothesized that: (1) premenstrual symptoms and sleep characteristics would explain greater luteal versus follicular phase psychophysiological reactivity, (2) symptoms and sleep characteristics would differentially predic...

The oviducts of 4 cows were cannulated and oviduct fluid was collected daily from the exteriorized cannulas for a total of 5 oestrous cycles. Daily serum samples were assayed for oestradiol-17 beta and progesterone to monitor the oestrous cycle. Data for each cycle were compared for oviduct fluid collected during the non-luteal phase (serum progesterone less than or equal to 1.5 ng/ml) and the ...

The present study was conducted to evaluate the endocrinological effects of the pituitary on luteal maintenance and regression in the cyclic golden hamster (Mesocritus auratus). After hypophysectomy (Hypox) at 0900 h on day 1 of the estrous cycle (the day of ovulation), the animals received injection of prolactin (PRL) or PRL plus equine chorionic gonadotropin (eCG). They were decapitated at 15...

Antioxidant enzymes seem to play roles in controlling the luteal function and the luteolytic action of prostaglandin F2α (PGF). The aim of this study was to clarify the roles of catalase (CAT) and glutathione peroxidase (GPx) in the luteolytic action of PGF in both corpus luteum (CL) and cultured luteal cells. Corpora lutea were collected at the early (days 2-3), developing (days 5-6), mid (day...