Soy Phytoestrogens Do Not Fully Reverse Changes in Rat Pituitary Castration Cells: Unbiased Stereological Study.

The aim of the study was to examine the potential of the principal soy isoflavones, genistein and daidzein, or isoflavone rich soy extract to recover pituitary castration cells in orchidectomized adult male rats in comparison with the effects of estradiol. Two weeks post orchidectomy (Orx), animals received estradiol-dipropionate, genistein, daidzein or soy extract subcutaneously for 3 weeks. Control sham-operated (So) and Orx rats received just the vehicle. Changes in the volumes of pars distalis, of individual follicle-stimulating hormone (FSH) and luteinizing hormone (LH) containing cells, their volume, numerical density and number were determined by unbiased design-based stereology. The intracellular content of ßFSH and ßLH was estimated by relative intensity of fluorescence (RIF). Orchidectomy increased all examined stereological parameters and RIF. Compared to Orx, estradiol increased the volume of pars distalis, but reversed RIF and all morphometric parameters of gonadotropes to the level of So rats, except their number. Treatments with purified isoflavones and soy extract decreased RIF to the control So level, expressing an estradiol-like effect. However, the histological appearance and morphometrical features of gonadotropes did not follow this pattern. Genistein increased the volume of pars distalis, decreased the volume density of LH-labeled cells and raised the number of gonadotropes. Daidzein decreased the cell volume of gonadotropic cells but increased their number and numerical density. Soy extract induced an increase in number and numerical density of FSH-containing cells. Therefore, it can be concluded that soy phytoestrogens do not fully reverse the Orx-induced changes in pituitary castration cells. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc.

What's in a Name? Roles of RFamide-Related Peptides Beyond Gonadotrophin Inhibition.

RFamide-related peptides (RFRPs) have been heavily implicated in the control of reproductive function subsequent to their discovery more than 16 years ago. However, recent studies using genetic and pharmacological tools have challenged their importance in regulating the hypothalamic-pituitary-gonadal axis. It is generally accepted that RFRPs act as part of a wider RFamide system, which involves two receptors, called the neuropeptide FF receptors (NPFFR1 and R2), and includes the closely-related neuropeptide NPFF. NPFF has been studied ever since the 1980s and many of the functions of NPFF are also shared by RFRPs. The current review questions whether these functions of NPFF are indeed specific to just NPFF alone and presents evidence from both neuroendocrine and pharmacological perspectives. Furthermore, recently emerging new functions of RFRPs are discussed with the overall goal of clarifying the functions of RFRPs beyond the hypothalamic-pituitary-gonadal axis.

The evaluation of estradiol and leptin action on the activity of the somatotropic and gonadotropic axes in peripubertal female rats.

OBJECTIVE: Available data suggest that estrogens and leptin play a role in the control of the pubertal process. In humans and some mammal species the increase of the activity of gonadotropic axis accompanies the decrease in the rate of growth at puberty. The effect of 17ß-estradiol and/or leptin administration on the somatotropic and gonadotropic axes was studied using prepubertal female rats as an animal model. MATERIAL AND METHODS: Prepubertal female rats received estradiol/saline, estradiol/leptin, oil/leptin or oil/saline (vehicles) respectively. The changes of growth rate, and serum 17ß-estradiol, leptin, GH, IGF-I and gonadotropins levels as well as LHRH and estrogen receptor (ER) concentrations in the medial basal hypothalamus (MBH) and the pituitary were determined. All hormones concentrations were measured by radioimmunoassay and ER by radioligand methods . RESULTS: In estradiol and/or leptin treated animals noticeable reduction of rate of growth was found. The decrease of growth in response to estradiol treatment accompanied the increase GH level and the decrease of IGF-I concentration in the circulation. Both hormones operating together activated reproductive axis, what was manifested by a significant increase of LHRH abundant in the hypothalamus as well as elevated LH and FSH levels in the circulation. In these rats a significant decrease of the estrogen receptor concentrations in the pituitary was observed. CONCLUSION: The role of estradiol and leptin in the control of growth and reproduction seems to overlap only partially. Estradiol plays a significant role in the activation of the reproductive axis, and leptin takes part as a permissive factor in pubertal process.

Effects of genistein on gonadotropic cells in immature female rats.

The effects of genistein on pituitary gonadotropic cells of immature female rats were examined and compared to actions of the synthetic estrogen, 17α-ethynylestradiol. Immature female rats received 50mg/kg/bw of genistein in dimethylsulfoxide (DMSO) subcutaneously (s.c.) daily for 3 days at 18, 19 and 20 days of age. A second group was injected with 1µg/kg of 17α-ethynylestradiol in olive oil in the same schedule. The genistein control group received DMSO only, while 17α-ethynylestradiol controls were given sterile olive oil only. Changes in cell number per mm(2), cell volume and volume density of follicle-stimulating (FSH) and luteinizing (LH) immunolabeled cells were evaluated by morphometry and stereology. Genistein induced significant increases in the number of FSH cells (by 21%) and LH cells (by 20%) per mm(2) compared to corresponding controls. Volumes of FSH and LH cells were significantly increased by 19.7% and 20% and their volume densities by 20% and 20.2%, respectively. Estradiol markedly affected gonadotropes in the same manner, but to a greater extent. It can be concluded that genistein acted as an estrogenic agonist in the pituitaries of immature female rats, and as such, stimulated gonadotropic cells.