Sex differentiation and development : proceedings of a symposium held at the Royal Scoiety of Medicine, Wimpole Street, London, on 10 and 11 April 1958 / edited on behalf of the Society for Endocrinology by C.R. Austin.

  • Symposium on Sex Differentiation and Development (1958 : London, England)
Date:
1960
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Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Sex differentiation and development : proceedings of a symposium held at the Royal Scoiety of Medicine, Wimpole Street, London, on 10 and 11 April 1958 / edited on behalf of the Society for Endocrinology by C.R. Austin. Source: Wellcome Collection.

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    SEX DIFFERENTIATION IN CRUSTACEA II endings which can be stained differently. In one of these types there is a sexual dimor¬ phism and it is likely that these endings are concerned with the secretion of sexual hormones. The ganglionic X organ, then, is the main centre of the hormone production of the complex, while most of the hormone is stored in the sinus gland. Panouse [1943-8], in a series of papers, showed that the sinus gland exerted an influence on the growth of the ovaries in the prawn Leander. He first showed that removal of the eyestalks from non-breeding female prawns led to a rapid increase in the size of the ovary, wloich within a month may have increased in weight more than seventy-fold. This increase in weight is accompanied by vitellogenesis, the appearance of the brooding characters at the next moult—owing no doubt to secretion of the appropriate hormone by the ripening ovary—and eventually to oviposition out of season. All these effects can be prevented by the implantation of a succession of sinus glands at regular intervals into the abdomina of prawns whose eyestalks have been removed. Panouse went on to show that removal of the sinus gland alone, leaving the rest of the eyestalk intact, leads to some increase in ovarian size, but not nearly so much as after complete eyestalk removal. Panouse's results have been abtindantly confirmed on a munber of species. I have found that injections of extracts of eyestalks, instead of implantation of sinus glands, are equally effective in preventing the consequences of eyestalk removal. Upon dissecting the eyestalk and preparing extracts of various fractions, I foimd the whole activity resided in the extracts of the sinus gland and of the ganglionic X organ. Other parts yielded inactive extracts. The active extracts, moreover, are effective in preventing the normal increase in ovarian size that precedes the breeding season. On the other side of the problem, I have found that removal of sinus glands together with the ganglionic X organs from non-breeding prawns is as effective as complete eyestalk removal in stimulating ovarian ripening. Removal of the X organ alone has little effect for about 10 days, but thereafter the rate of increase of the ovary is as great as after eyestalk removal. It seems that there is sufficient hormone stored in the sinus gland to last for 10 days. Taken in conjunction with the other evidence on the mode of functioning of the X organ-sinus gland complex, I think these observations sufficiently demonstrate that the complex produces a hormone that inhibits ovarian ripening. This is the hormone to which Dr Butler refers in the preceding paper. It is active in inhibiting the ovarian growth of honeybees, while the queen substance of bees injected into prawns inhibits their ovarian growth. Large doses of androsterone exert a similar effect; so, to a certain extent, do testosterone and methyl testosterone. Nine other steroids, supphed by Dr Callow, which I have tested had no ovary-inhibiting effect. Assay of the amounts present in the sinus glands of prawns at different times of the year reveal that it is present in steady amounts in males all the year round, while in the female there is a seasonal variation, the content dropping to nil shortly before the breeding season [Carlisle, unpublished data]. Essentially the same situation appears to exist in the control of the ovarian functioning of crabs, lobsters and crayfish. In the male, however, there is a noteworthy difference between crabs and pravms. Démeusy [1953] has shown, and I have since confirmed,