title: Seasonal changes in testicular contents of testosterone and androstenedione and in the metabolic clearance rate of testosterone in the sand rat (Psammomys obesus).
abstract: Adult male sand rats (Psammomys obesus) were caught in the Béni-Abbès area. The highest testicular contents of androgens (ng/testis) were observed in autumn and in winter (testosterone: 7.6 +/- 1.1; androstenedione: 0.76 +/- 0.11) and the lowest in early summer (June) (testosterone: 1.5 +/- 0.3; androstenedione: 0.20 +/- 0.05). Values had increased by late July. Annual variations of the testosterone metabolic clearance rate (litres/24 h/100 g body wt) were similar to those of testicular androgens; values were high in winter (6.7 +/- 0.7) and lowest in June (3.2 +/- 0.3). The onset of testicular endocrine activity in sand rats was concomitant both with the highest temperatures and the start of reduction in photoperiod; its regression occurred when temperature and photoperiod were increasing.
mesh_terms: D000735:Androstenedione / Q000378:metabolism*; D000818:Animals; D003411:Arvicolinae; D008297:Male; D008657:Metabolic Clearance Rate; D009929:Organ Size; D012621:Seasons; D012669:Seminal Vesicles / Q000033:anatomy & histology; D013696:Temperature; D013737:Testis / Q000033:anatomy & histology / Q000378:metabolism*; D013739:Testosterone / Q000378:metabolism*
chemical_list: D013739:Testosterone; D000735:Androstenedione