HOME HELP CONTACT US SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by KAMYAB, S. Articles by FOTHERBY, K. Search for Related Content PubMed Articles by KAMYAB, S. Articles by FOTHERBY, K.

After injection of [4-¹⁴C]norethisterone or norgestrel labelled with ¹⁴C in the ethynyl group into rabbits, 45% and 57·4% of the radioactivity was excreted in the urine, mostly within 2 days. Although small amounts of radioactivity were excreted in the expired air of rabbits receiving norgestrel, little metabolism of the ethynyl group occurred. Radioactivity in plasma declined quickly after injection and 24 hr. later less than 0·5% of the dose remained in the circulation. Up to 5 hr. after injection large amounts of radioactivity were found in liver, kidney, intestine and bile; a large proportion of the dose appeared to undergo an entero-hepatic circulation. Although the concentration in fat and muscle was low the total amount in these tissues may approach 5%. The uterus contained a high concentration of radioactivity suggesting that this tissue may bind the progestins or their metabolites. By 24 hr. the amount of radioactivity in the tissues had markedly decreased. Small amounts of radioactivity crossed the placenta of pregnant animals near term and small amounts were found in the foetus and amniotic fluid. Within 3 hr. of the injection at least half of the radioactivity in the tissues was in a conjugated form and considerable metabolism of the injected progestins had occurred. Little, if any, norethisterone or norgestrel was present in the tissues. The metabolites of norethisterone were mainly polar compounds showing that hydroxylation of the steroid had occurred, whereas the metabolites of norgestrel appeared to be similar to the compounds produced by partial or complete reduction of the ,β-unsaturated ketone grouping in ring A.