So everyone was working on partial syntheses of steroid horm... of cortisone. But all the other hormones, testosterone, progesterone, deoxycorticosterone had already been introduced into medicine. So how did they do it? That was done primarily by these European companies, Ciba, Roche, Organon a Dutch company, Schering a German company, Schering, Berlin based on academic research by German chemists and Swiss chemists. And they did it primarily from two raw materials. The most important was cholesterol because cholesterol is also a sterol... a steroid, and that you can isolate fairly readily from... from slaughterhouses... from animals because the constituents of... particularly of brain tissue and... Then there are some other, there are some plant sterols like soil sterols, stigmasterol, or wheat or germ sterols, sitosterol. But these are all very closely related to cholesterol and the conversion of cholesterol to these hormones was difficult but had been accomplished and that was the source... the industrial source of these compounds. That made them very expensive. It is much more difficult to do this in the case of... of steroids, of... of oestrogens and I think I should... I think I have here some pictures that probably would show this best. Yeah. I want to find an easy one. Is this funny? Yeah, here. For instance, if you’re looking at these structures here, you see here the structure of the male sex hormone testosterone and the structure of one of the female sex hormones, progesterone. You don’t have to be a chemist at all because if you look at these two there’s really only one difference and that is way up here. Testosterone has an OH and progesterone has a COCH3. Except for that they’re identical. Yet that is a tremendous difference. The female sex hormone responsible... particularly important in pregnancy and this is the male sex hormone.

Now, as far as oestrone or estradiol, the oestrogenic hormones, are concerned, because they are two female sex hormones, progesterone and oestrone or estradiol... see there the fundamental difference about the oestrogenic ones. You can see the difference in its outline in black. It does not have this type of ring. It has an aromatic ring, which is called really a benzene ring, and it lacks this solid figure which is a methyl group. So, the methyl group here blocks the aromatisation of this ring. You have to remove it in order to convert it. That... that was my PhD thesis. You obviously took a hell lot more than just drawing one step and it wasn’t just one step, but the removal of this methyl group from testosterone, a very difficult position, into the oestrogen is what I worked on. The difference between male and female sex hormones is only one carbon atom. The difference between you and me is only one carbon atom in a very fundamental way. And you could say the most important carbon atom in the world it separates really the difference chemically between male and female, and I really worked on the question of how do you eliminate that one carbon atom.

The reason why I’m emphasising this is because this will lead eventually to a discussion of the pill.  But so these... so this was, for instance, synthesised from cholesterol by quite a number of steps and this was synthesised cholesterol. But at that time there was no way of synthesising this. So even though oestrone estradiol was used in medicine, the only place you can get it was isolating in hundreds of thousands of litres of urine. Initially actually of pregnant women... of women. Later on, of pregnant mares and to this day one still isolates quite a bit of it that way. But I, of course, was interested in seeing if we can develop an industrial chemical transformation and that was in part... part of my PhD thesis.