Circadian pattern of prolactin and growth hormone levels in female rats of two strains.
Plasma growth hormone and prolactin levels were determined by radioimmunoassay at intervals of 2 hr during the light phase of a controlled light-dark cycle in virgin female (COBS F/Crl BR) and [Sch:SPD(SD)BR] rats. Peak prolactin concentrations were observed in the afternoon during proestrus and estrus in both rat stocks. Growth hormone exhibited wide fluctuations in the Sch:SPD rat, attaining peak levels at 1300 hr, but no apparent periodicity was observed in the COBS rats.
D000818:Animals; D002940:Circadian Rhythm; D004971:Estrus; D005260:Female; D013006:Growth Hormone / Q000097:blood*; D008027:Light; D011247:Pregnancy; D011359:Proestrus; D011388:Prolactin / Q000097:blood*; D051381:Rats / Q000097:blood*; D013045:Species Specificity
D011388:Prolactin; D013006:Growth Hormone