Steroidogenic activity of the placenta, corpus luteum and blood of the African elephant, Loxodonta africana

Abstract

The study was directed at expanding our understanding of the endocrine correlates of pregnancy in the African elephant (Loxodonta africana). This information is considered important for the potential development of techniques to manipulate the reproductive output of female elephants in attempts to control the size of populations in confined areas. During the gestation period no obvious trends for the concentrations of progesterone and 5adihydroprogesterone could be illustrated. The concentrations of both progestins were higher in pregnant than in non-pregnant females. Circulating concentrations of 5a-dihydroprogesterone were higher than that of progesterone in pregnant animals, but not in non-pregnant females or foetuses. Concentrations of oestradiol-17P were low in all the samples tested. Pregnenolone was converted to polar compounds by placenta. Progesterone was the principal metabolite in blood. Corpora lutea were the main sites for the synthesis of 5a-reduced metabolites and therefore provide the most suitable site for possible control.