Wildlife Damage Management, Internet Center for


Date of this Version

September 1970


This talk today will be on recent developments with Ornitrol. All the recent developments have been with blackbirds and grackles; and, unfortunately, the man who has done the most recent work is sitting right here, so I can't steal his data very well!

We have done some work since I spoke to you last on some of the pharmacol¬ogy of SC-12937--which is an axocholesterol the active ingredient of Ornitrol. One of these developments is the determination of the half-life of SC-12937, which is 28 days. This is the reason, we feel, for its prolonged activity in birds. It is stored in the liver. It is metabolized at this rate, and excreted. It interferes with several liver functions, and this is how the material takes its affect.

Ornitrol affects the synthesis of cholesterol, which is connected in turn with egg yolk formation, and also we think with egg yolk membrane formation. Recently, we have come to find that it interferes, in mammals at any rate, with lipid synthesis. Our endocrinologists tell us that it has an effect on the adrenals, which may have an effect on the pituitary and an influence thereby on estrogen production which is con¬cerned with spermatogenesis in the male through the Sertoli cells. Some of this infor¬mation is postulated, and some of it we have shown to be fact.

Mammalian data on cholesterol and the lipid levels are very adequate. Work done at Urbana a few years ago, when the material was fed for a long period of time, seven weeks, showed that a percentage of birds, on subsequent post mortem, did not appear to have any gonads; or at least the gonads could not be found. If they had gonads, they were so small and so atrophied that they could not be found. We really didn't attach very much importance to this, of course. I now realize that this wasn't very wise. But it did show that prolonged interference with the synthe¬sis of cholesterol and lipids has a permanent effect on the ovaries in these pigeons.