Unexpected plasma gonadal steroid and prolactin levels across the mouse estrous cycle.

Endocrinology(2023)

Cited 3|Views9
No score
Abstract
Despite the importance of the mouse in biomedical research, the levels of circulating gonadal steroids across the estrous cycle are not established with any temporal precision. Using liquid chromatography-mass spectrometry, now considered the gold standard for steroid hormone analysis, we aimed to generate a detailed profile of gonadal steroid levels across the estrous cycle of C57BL/6J mice. For reference, luteinizing hormone (LH) and prolactin concentrations were measured in the same samples by sandwich ELISA. Terminal blood samples were collected at 8-hour intervals (10 am, 6 pm, 2 am) throughout the four stages of the estrous cycle. As expected, the LH surge was detected at 6 pm on proestrus with a mean (±SEM) concentration of 11 ± 3 ng/mL and occurred coincident with the peak in progesterone levels (22 ± 4 ng/mL). Surprisingly, estradiol concentrations peaked at 10 am on diestrus (51 ± 8 pg/mL), with levels on proestrus 6 pm reaching only two-thirds of this value (31 ± 5 pg/mL). We also observed a proestrous peak in prolactin concentrations (132.5 ± 17 ng/mL) that occurred earlier than expected at 2 am. Estrone and androstenedione levels were often close to the LOD and showed no consistent changes across the estrous cycle. Testosterone levels were rarely above the LOD (0.01 ng/mL). These observations provide the first detailed assessment of fluctuating gonadal steroid and reproductive hormone levels across the mouse estrous cycle and indicate that species differences exist between mice and other spontaneously ovulating species.
More
Translated text
Key words
estradiol, progesterone, luteinizing hormone, prolactin
AI Read Science
Must-Reading Tree
Example
Generate MRT to find the research sequence of this paper
Chat Paper
Summary is being generated by the instructions you defined