INVESTIGATIONS ON THE ADRENOCORTICAL FUNCTION OF NORMAL DOGS

Abstract

SUMMARY The median urinary excretion of 17-oxosteroids in 22 normal unanaesthetized dogs was 0·06 (range: 0·02–0·24) mg./kg. body weight/24 hr. 17-Oxosteroid excretion increased markedly after the administration of dehydroepiandrosterone and androstenedione, while testosterone caused only a very small increase. The median urinary excretion of total 17-hydroxycorticosteroids (17-OHCS) in 21 dogs was 0·16 (range: 0·06–0·320 mg./kg. body weight/24 hr. This was calculated to amount to about 50–60% of the cortisol produced. Stimulation with corticotrophin (ACTH) resulted in an increase of urinary 17-OHCS and of plasma 11β-OHCS levels, but 17-oxosteroid excretion was only slightly increased. In 27 dogs the median plasma 11β-OHCS level was 4·0 (range: 1·3–9·7) μg./100 ml. at 8.00 hr. and 3·6 (range: 0·4–7·0) μg./100 ml. at 17.00 hr. In eight dogs 3-hourly plasma 11β-OHCS estimations were done; six of these animals showed a diurnal variation comparable to that in man.