Spermatogenesis Following Early Ovariotomy in the Brown Leghorn Fowl. ∗

Abstract

In our earlier series of experiments on ovariotomy 1 operations were performed at a relatively late age, the majority of the birds ranging from 3 to 8 or 9 months. One of the extraordinary results revealed was the development of the rudimentary right gonad into an organ which is essentially a testis though, in our cases, always sterile. This was particularly baffling since during the course of our study 2 cases of spermatogenesis were recorded by Benoit 2 and 1 by Zawadowsky 3 in the ovariotomized fowl, from a relatively insignificant number of experiments. These birds were 4, 27, and 45 days of age respectively at the time of operation. Only 2 of our cases, one of 2, and one of 27 days, came within this age range.

Furthermore, according to the work of Brode 4 and others 5 , 6 primordial germ cells are present in the medulla of both right and left gonads of the female chick in early stages. Brode has shown that these cells gradually decrease in numbers after hatching so that by approximately 3 weeks after they have practically all disappeared in the right gonad. Since it is highly probable from these observations that no primordial germ cells were present in the right rudimentary gonad at the time of ovariotomy in our earlier series it was considered advisable to supplement this otherwise extensive data by additional cases of early ovariotomy.

A large number of females were ovariotomized at an early age. Operations were performed every day from the first to the 30th day, and every other day from the 30th to the 50th day, after hatching. 175 birds operated under 30 days of age survived the operation; of these, 26 had been operated during the first 7 days. The birds were killed at regular intervals and the material carefully preserved. The study is not complete. Forty birds are still alive, and the gonads of those killed have not all been studied histologically. The experiments, as previously, were confined to the single comb light brown Leghorn secured from the same source immediately after hatching.