Prolactin and Lutenizing hormone levels during diestrus and proestrus in mice

Prolactin secretion patterns are species-specific, variable and influenced by multiple factors including circadian and hormonal cues, stress, physiological state and reproductive strategy. In nonpregnant females, circulating prolactin levels are low; however, during the afternoon of proestrus an estradiol-induced prolactin surge coinciding with the preovulatory LH surge has been recorded in many (but not all) species. In mice, there have been conflicting reports relating to the occurrence and timing of this surge. To gain insight into the characteristics of circulating prolactin levels during proestrus we have used repeated tail tip blood sampling in C57BL/6J and Swiss Webster mice to profile prolactin secretion in individual mice. For this study we have measured prolactin levels during diestrus and proestrus using an ultra-sensitive prolactin ELISA. To establish the relationship between circulating prolactin levels and the timing of the LH surge we have simultaneously measured LH level...