Adrenocortical hormones in the neonate and pouch young of the tammar wallaby, Macropus eugenii.

Abstract

Departments of Zoology, Australian National University, Canberra and St Bartholomew's Medical College, London, EC1M 6BQ (Received 16 December 1975) The adrenal cortex of many eutherian mammals is functional at birth and in some species at least may be involved in parturition (e.g. Liggins, Kennedy & Holm, 1967). Marsupials are born after a relatively short gestation and are considerably smaller than eutherian neonates. It has been postulated that the middle of pouch life, when homoiothermy is achieved, is comparable to the time of birth in eutherians (Bentley & Shield, 1962). Homoiothermy in the tammar wallaby, Macropus eugenii, is established between 140 and 170 days of pouch life (Setchell, 1974). Experiments were designed to determine when the adrenal cortex begins to synthesize and secrete steroids. Male pouch young of the tammar wallaby were bled from the carotid artery, and steroids were extracted with methanol. Adrenals were weighed, chopped and incubated (Vinson, Phillips,