Oestradiol-17 beta and prolactin levels in rat peripheral plasma

Area of Science:

• Endocrinology
• Reproductive Biology
• Animal Physiology

Background:

• Accurate measurement of reproductive hormones is crucial for understanding rat estrous cycles.
• Radioimmunoassay (RIA) is a common technique for hormone quantification.

Purpose of the Study:

• To evaluate the reliability of RIA for determining oestradiol-17 beta and prolactin concentrations in rat plasma.
• To investigate the variations in these hormone levels across different stages of the estrous cycle and in ovariectomized rats.

Main Methods:

• Radioimmunoassay (RIA) was employed to measure plasma oestradiol-17 beta and prolactin levels.
• Hormone concentrations were analyzed in plasma samples from male and female rats at various stages of the estrous cycle.
• Factors influencing prolactin measurements, such as blood collection method and sample type, were considered.

Main Results:

• Prolactin was detectable in all samples, with concentrations varying significantly between rats, even within the same estrous cycle stage.
• Estradiol-17 beta concentrations were below the assay sensitivity in ovariectomized females.
• Estradiol-17 beta levels increased from metoestrus to proestrus and decreased during oestrus.
• Prolactin levels were lowest in the afternoon of diestrus and surged in the afternoon of proestrus.
• Prolactin concentrations were affected by blood collection method, hemolysis, and plasma vs. serum.
• No correlation was found between prolactin and oestradiol-17 beta levels in the same plasma sample.

Conclusions:

• RIA methods provide a means to measure estradiol-17 beta and prolactin in rat plasma.
• Both hormones exhibit dynamic changes related to the estrous cycle, with prolactin showing greater variability.
• Careful consideration of sample handling and collection is necessary for reliable prolactin measurements.