Annual profiles of reproductive hormones in peripheral plasma of the male roe deer (Capreolus capreolus).

Blood samples were collected from 3 roebucks 1 to 3 times per month during several years to study the relationship between season and concentrations of LH, FSH, testosterone and prolactin. Plasma values of all of these hormones began to increase during the second half of February. LH, FSH and testosterone levels reached a plateau during April. Highest average levels of LH and testosterone were observed before the start of the rutting season (mid-July--mid-August) and steadily declined thereafter. In contrast to LH and testosterone, FSh concentrations decreased 6 weeks earlier, during June, indicating a modulated secretion pattern. Prolactin steadily increased until the beginning of July and then decreased.