Peak Levels Of Progesterone Research Articles

Seasonal Effects on Body Condition and Characteristics of the Estrous Cycle in Captive Asian Elephants (Elephas maximus) in Thailand: A Retrospective Study.

The aim of this study was to investigate the effects of season on the body condition score (BCS), the characteristics of the estrous cycle (luteal phase [LPL], follicular phase [FPL], estrous cycle [ECL] lengths, and the start of the luteal phase [SLP] and follicular phase [SFP]), and progesterone levels (baseline and peak) of eight captive Asian elephants (Elephas maximus) in Thailand. From 2014 to 2019, blood samples were collected weekly for serum progesterone enzyme immunoassays (EIAs). Estrous cycles (n = 70), including the luteal and follicular phases, and BCS (n = 70) were recorded. Based on the BCS, the LPL, FPL, and ECL were assigned to the following two groups: normal (BCS = 3.0-4.0, n = 38) and overweight (BCS = 4.5-5.0, n = 32). The findings demonstrated that there was no difference in LPL between the groups. However, in the normal group, the ECL was one week longer (14.9 ± 1.7 vs. 13.9 ± 1.7 weeks; p < 0.05), and the FPL also tended to be one week longer (7.2 ± 1.7 vs. 6.4 ± 1.5 weeks; p = 0.06) than in the overweight group. The mean progesterone level during the rainy, hot, and cool seasons was not statistically different. Based on the yearly averaged BCS from three seasons, the baseline and peak levels of progesterone were classified into the normal (n = 16) and overweight (n = 12) groups. Females with a normal BCS tended to exhibit higher progesterone peak levels (p = 0.08). The majority of peaks appeared during the rainy season (53.57%). The BCS was highest during the hot (4.47) and rainy (4.38) seasons, but not during the cool (4.12) season. The LPL, FPL, and ECL were not affected by the season in which the luteal phase occurred. On the other hand, the rainy season had a significant effect on the SFP, resulting in a longer LPL (p < 0.05) and ECL (p = 0.01); both were the longest during the rainy season. In conclusion, the effects of season on BCS may be related to characteristics of the estrous cycle and peak progesterone levels. Ultimately, these findings provide ground knowledge to assist elephant managers and owners in planning breeding activities using seasonal effects and BCS measurements in tropical climates.

The menstrual cycle and the skin.

Perimenstrual exacerbations of dermatoses are commonly recognized, yet our knowledge of the underlying pathophysiological mechanisms remains imperfect. Research into the effects of oestrogen on the skin has provided evidence to suggest that oestrogen is associated with increases in skin thickness and dermal water content, improved barrier function, and enhanced wound healing. Research into the effects of progesterone suggests that the presence of various dermatoses correlates with peak levels of progesterone. Dermatoses that are exacerbated perimenstrually include acne, psoriasis, atopic eczema and irritant dermatitis, and possibly also erythema multiforme. Exacerbations occur at the peak levels of progesterone in the menstrual cycle. Underlying mechanisms include reduced immune and barrier functions as a result of cyclical fluctuations in oestrogen and/or progesterone. Autoimmune progesterone and oestrogen dermatitis are the best-characterized examples of perimenstrual cutaneous reactions to hormones produced during the menstrual cycle. In this review, we describe the current understanding of the menstrual cycle, and its effect on the skin and cutaneous disorders.

Changes in progesterone levels and distribution of progesterone receptor during vitellogenesis in the female mud crab (Scylla paramamosain)

Vertebrate-type steroids, such as progesterone, have been identified in crustaceans. The physiological activity of progesterone during vitellogenesis is still not well understood. In this study, progesterone levels in the female mud crab, Scylla paramamosain, were determined by enzyme-linked immunosorbent assay. Peak levels of progesterone were detected during the previtellogenic stage in the hemolymph, ovary, and hepatopancreas, whereas the progesterone level decreased significantly in vitellogenic stage I. During vitellogenic stage II, progesterone levels rose again in the hemolymph and ovary, but continued to decrease in the hepatopancreas. By using western blotting, progesterone receptor (PR), with an apparent molecular weight of 70 kDa, was identified in the ovary during both vitellogenic stages I and II. By means of immunohistochemistry, PR was detected mainly in the follicle cells during vitellogenic stage I and in the nuclei of oocytes in vitellogenic stage II. Our results strongly suggest that progesterone promotes vitellogenesis in the mud crab, S. paramamosain via a classical genomic mechanism.

Initiation of periovulatory events in primate follicles using recombinant and native human luteinizing hormone to mimic the midcycle gonadotropin surge.

The amplitude and duration of the midcycle LH surge required for periovulatory changes in the primate follicle are incompletely defined. We reported that short (4- to 14-h) LH surges were insufficient to induce periovulatory events after multiple follicular development in macaques. In contrast, an 18- to 24-h LH surge induced oocyte maturation plus granulosa cell luteinization, but did not support corpus luteum function. In this study, the periovulatory changes following LH surges of 48 h elicited using pituitary (pit) or recombinant (r) human (h) LH were compared to those after 24-h LH surge durations or after urinary hCG (u-hCG) treatment. Beginning at menses, rhesus monkeys were treated with human gonadotropins for 9 days to stimulate follicular growth. On day 10, animals (n = 3-5/group) received 1) a single injection of u-hCG [79 +/- 3 micrograms RP-1 equivalents (equiv), im], 2) two injections of pit-hLH (91 +/- 4 micrograms RP-1 equiv, im), 3) one injection of r-hLH (21 +/- 1 micrograms RP-1 equiv, im), or 4) two injections of r-hLH (21 +/- 1 micrograms RP-1 equiv). Oocytes and granulosa cells were obtained via follicle aspiration 27 h after the initial LH or hCG injection. In all groups, serum estradiol rose to similar peak levels by day 10. Circulating LH-like bioactivity was elevated for more than 48 h after u-hCG. Peak serum LH bioactivities were proportional to the administered LH doses, as determined in the in vitro bioassay. Two injections of either r-hLH or pit-hLH elicited surge levels (> 100 ng/mL) of bioactive LH for 36-48 h, whereas one injection sustained surge levels for only 18-24 h. The proportions of oocytes resuming meiosis (68-76%) were similar in all groups. Immunocytochemical staining for progesterone receptor and in vitro progesterone production by granulosa cells in all LH-treated groups were comparable to those of cells form the hCG-treated group. Peak levels of progesterone in the luteal phase were comparable in monkeys treated with two doses of pit-hLH and r-hLH (18.5 +/- 10.4 vs. 8.1 +/- 1.5 ng/mL) and approached that in u-hCG treated monkeys (39.5 +/- 18.0 ng/mL). However, progesterone levels in animals treated once with r-hLH (3.4 +/- 1.5 ng/mL) were less (P < 0.05) than those in u-hCG-treated monkeys.(ABSTRACT TRUNCATED AT 400 WORDS)

Adrenal effects of low-dose aminoglutethimide when used alone in postmenopausal women with advanced breast cancer

Aminoglutethimide (Ag) is a potent aromatase-enzyme inhibitor used in the treatment of patients with breast cancer. In the past, it has been administered in doses of 1,000 mg/d (usually with 40 mg hydrocortisone). At these dose levels, the drug also affects multiple cytochrome P-450 enzymes, including enzymes for adrenal steroid biosynthesis. Recently, lower-dose regimens (500 mg/d) of Ag have been found to be just as effective for breast cancer therapy, but less toxic than the higher conventional dose. There is limited information on the adrenal effects at the lower dosages, and it is not known whether these effects are clinically significant. We measured basal and synthetic corticotropin (Cortrosyn)-stimulated levels of adrenal steroids in postmenopausal breast cancer patients before and during treatment with low-dose Ag (500 mg/d) administered without a glucocorticoid preparation. Basal levels of progesterone, 17-OH progesterone, and 11-deoxycortisol were higher after 2 months' treatment ( P < .01). After ACTH injection, peak levels of progesterone and 17-OH progesterone were higher ( P < .01), but in contrast, peak levels of 18-OH corticosterone were lower during treatment ( P < .02). Basal and peak levels of cortisol, aldosterone, and all other adrenal steroids were unchanged during treatment. We conclude that low-dose Ag treatment leads to partial inhibition of the 21-hydroxylase, 11-hydroxylase, and 18-hydroxylase adrenal enzymes. Since cortisol and aldosterone secretion remained normal with minimal shunting to or accumulation of adrenal androgen compounds, we believe that the mild inhibition was compensated for by further endogenous ACTH stimulation.

Annual cycle of gonadal histology and steroid profiles in the juvenile males and adult females of the protandrous black porgy, Acanthopagrus schlegeli

The objectives were to investigate the changes in gonadal histology and plasma levels of gonadal steroids from the bisexual to the male phase in the juvenile male black porgy, Acanthopagrus schlegeli. The reproductive cycle in the adult females was also studied. The gonad consisted mainly of testicular tissue at 5 months of age. The ovarian tissue in the stage of primary oocytes was well developed at 7 months of age. The gonad underwent an intensive spermatogenesis at 9 months of age. During the first and second spawning season, the testicular tissue was dominant, which made the fish male. The ovarian tissue became dominant at 18 months of age during the non-spawning season. The chronological order of histological features in black porgy was suggested to be testicular, bisexual, male, bisexual, male, and female. Maximum plasma levels of estradiol-17β and testosterone occurred simultaneously before the first spawning season in juvenile males and might have an important function in spermatogenesis. For females, gonadosomatic index, oocyte diameter, and levels of estradiol-17β and testosterone increased during the spawning season. Peak levels of progesterone and 17α-hydroxyprogesterone were not observed in juvenile males and adult females during the spawning season.

Premenstrual changes and changes in gonadal hormones.

Changes in plasma levels of estradiol and progesterone and their temporal relationship with changes in mood and behavior were studied along the menstrual cycle in 17 normal women with a wide range of severity and types of premenstrual changes (PMC). Emphasizing changes in hormonal levels over time as well as their rates of change, selective clinical features of premenstrual changes were found to be positively associated with peak levels of progesterone, its rate of decrease over time, and the ratio between the rates of decrease-over-time of progesterone and estradiol levels. A time-lag of 4-7 days between changes in plasma levels of progesterone and changes in clinical features was also found. Rate of change of estradiol was somewhat associated with clinical PMC. It is suggested that the association between gonadal hormones, other biological changes, and mood should be further studied as a diversified, dynamic, time-related process.

Serum levels of oestradiol-17 beta and progesterone in relation to sexual receptivity in intact and ovariectomized rats.

Serum levels of oestradiol-17 beta fluctuated markedly during the oestrous cycle or rats. The onset of sexual receptivity occurred in close correlation with increasing serum levels of progesterone. The serum levels of oestradiol and progesterone in ovariectomized rats implanted with constant-release implants filled with oestradiol or progesterone were related to the amount of hormone in the implants. Constant low serum levels of oestradiol stimulated sexual behaviour in ovariectomized rats, but progesterone stimulation was required for maximum behavioural responses. Peak levels of progesterone in the serum during the oestrous cycle were much higher than those needed for induction of the behaviour in ovariectomized, oestradiol-treated rats. Progesterone, administered in physiological doses, inhibited the induction of sexual receptivity caused by oestradiol and progesterone and the inhibition depended on the strength of the stimulation with oestradiol.

Role of progesterone in implantation in the sheep.

Merino ewes were ovariectomized on Days 4 8 or 12 of pregnancy and injected daily from that time with 1- 4- or 16-mg progesterone in oil. The ewes were killed on Day 20 and examined for embryos. Sections of uteri were examined histologically. There was a clear effect of dose of progesterone on the number and viability of embryos. Of the ewes receiving 1- 4- and 16-mg progesterone there were 0/12 2/11 and 11/14 with viable embryos on Day 20. The effect of increasing progesterone was also seen in significantly increased glandular and luminal epithelial cell heights in ewes receiving 16 mg day. Plasma progesterone was measured daily during Day 1-5 and twice daily during Days 6-15 of pregnancy of of the estrous cycle. The number of corpora lutea and embryos in these animals was verified at laparotomy on Days 16-18. Mean plasma progesterone in pregnant and nonpregnant ewes did not differ significantly until Day 16. The individual pattern of progesterone levels was characterized by a large (up to 16 ng/ml) and transient peak in the period from Days 11-14. Different ewes had peak values at different times so that the mean progesterone values took the form of a variable plateau of 2-3 ng/ml lasting several days. Peak levels of progesterone appear in the plasma at times consistent with the idea that this hormone is responsible for the rapid preimplantation growth phase of the embryo during Days 11-15.(FULL TEXT)