THE ANTERIOR LOBE OF THE CATTLE PITUITARY

Abstract

A histological examination has been made of the anterior lobe of the pituitaries from forty-five female and fifteen male cattle classified into groups according to reproductive condition. Differential counts for the two main secretory cell types have been made on sections at three levels and values for each group compared by analysis of variance. Statistical treatment of results has shown that the method in which cell counts are made on one, or at the most two representative sections only from each of a number of glands is sufficiently accurate for comparative investigations, covering groups of cattle. Only one type of acidophil cell was observed, but both 'strong' and 'weak' basophils were found. 'Strong' basophils appeared to be more frequent in glands from pregnant and stilboestrol-treated cows but were virtually absent in those from steers. A significant difference has been found in the numbers of acidophil cells, between pituitaries from cows with normal ovaries and from those with ovarian follicular cysts. In the first trimester of pregnancy the number of basophils was significantly higher than in normal non-pregnant cows. The relative numbers of these two cell types in pituitaries from cows treated with large doses of stilboestrol were comparable with those in pregnant cows. There was a significantly greater acidophil number for both bulls and steers than for any of the cows. The basophil number for steers was significantly less than that for bulls or cows.