An endocrine and histophysiological study of the testicular annual cycle in the hedgehog (Erinaceus europaeus L.)

The Cycle of the Seminiferous Epithelium of the Turkish Hamster (Mesocricetus brandti)

“…Whether cycle duration varies with reproductive state cannot be extrapolated directly from total length, but the lack of effect of the state of hibernation on the spermatogenic cycle of the hedgehog (8) or short photoperiod in the vole (15) suggest that this timing is fixed. However, in a lower form, the snail (Helix aspersa), delay in the transition from spermatocyte II to spermatid in response to short photoperiod has been reported (13).…”

Sex Steroid and Prolactin Profiles in Male American Black Bears (Ursus americanus) during Denning.

“…It has been established that the onset of spermatogenic activity occurs during the denning period in black bears [5,24] and brown bears [25] as well as in other deep hibernating mammals such as ground squirrels [10,12], European hedgehogs [4,21], and golden hamsters [22]. Serum testosterone profiles of black bears indicated that the activity of the reproductive endocrine system begins to increase during denning [11,17,24].…”

Seasonal endocrine cycles in the European hedgehog, Erinaceus europaeus

“…The lack of correlation of ß-endorphin with plasma or urinary cortisol suggests that it is not simply secreted from the anterior pituitary simultaneously with ACTH, as occurs in response to treatment with corticotrophin-releasing factor (Vale et al, 1978) or stress (Guillemin et al, 1977). The rise in ß-endorphin values between January and March correlates with plasma testosterone and thyroxin elevation, suggesting a role for ß-endorphin in both the reactivation of gonadal activity which occurs at this time Walin et al, 1968;Dutourné & Saboureau, 1983) and the stimulation of anabolism (Margules, 1979). However, the suppression of LH secretion by ß-endorphin (Ebling & Lincoln, 1985) contradicts a progonadal role for ß-endorphin, although its antigonadotrophic effect is modulated by gonadal steroids themselves (Bhanot & Wilkinson, 1984).…”

“…Despite variation (Saboureau & Peyre, 1970), full testicular reactivation, with mature spermatocytes present in the epididymides, usually occurs before April in south-west France. Since peak plasma testosterone values are attained 1 month before full spermatogenesis (Saboureau, 1981;Dutourné & Saboureau, 1983), returning to basal levels 1 month before semi¬ niferous tubule regression, circulating testosterone concentrations are an accurate reproductive index. During the first half of hibernation spermatogenesis remains at the primary spermatocyte stage (Allanson, 1934;Saure, 1969), testicular reactivation recommencing from mid-hibernation 'Present address: Department of Bio-Medical Physics, University of Aberdeen, Aberdeen AB9 2ZD, U.K. (Saboureau, 1979), while the hedgehogs have low body temperatures for much of the time (Fowler, 1986).…”