152 SECTIONAL ADDRESSES 
so treated may survive for six months without recourse to the use of 
insulin. ‘The animals lost weight, but there were occasional periods 
during which they actually gained weight. Hypoglycemia was a feature 
of the condition and some of the dogs required injections of glucose to 
keep them alive. Houssay believes that the pituitary is antagonistic to 
the pancreas in carbohydrate metabolism, and that the anterior lobe is 
the main factor. It is of interest to note that Houssay and Biasotti found 
that injury to the tuber cinereum or to the mammillary bodies has no 
influence upon the course of pancreatic diabetes. 
Baumann and Marine have produced glycosuria and hyperglycemia 
in rabbits by the daily injection of the anterior lobe, and Evans and his 
co-workers obtained the same result in two out of four dogs by the daily 
injection of the growth hormone continued for eight or nine months. 
Repeated injections of anterior lobe extracts have also been found to 
produce ketonuria, lipzemia and cholesterolemia, in addition to hyper- 
glyceemia and increased resistance to insulin. 
Tue PosTERIOR LOBE. 
The posterior lobe furnishes an extract, pituitrin, which is rich in 
physiological activity, but which has not so far been separated into more 
than two fractions, each possessing its own definite properties. The 
pressor effect was discovered by Oliver and Schafer in 1895, and located 
to the posterior lobe by Howell. ‘There are anomalies in its action upon 
the circulation. A second dose within half an hour of the first produces 
a fall in blood pressure. Noél Paton and Watson found that it has no 
pressor effect in the bird, and Hogben and Schlapp showed that it has 
no perceptible action upon the circulation of the tortoise and frog. On 
the other hand Krogh and Rehberg found that removal of the pituitary 
in the frog results in a generalised capillary dilatation, which may be 
overcome by the injection from time to time of small amounts of pituitrin. 
Krogh believed that the secretion of the posterior lobe is essential for the 
preservation of capillary tone, and this view has obtained wide acceptance. 
No part of the pituitary, other than the pars nervosa, yields an extract 
which has a pressor action upon the mammalian circulation though some 
of the other actions of pituitrin are obtainable from extracts of the pars 
intermedia. ‘This of itself is evidence of there being at least two active 
principles in pituitrin, and confirmation came from the work of Kamm, 
Aldrich and others in the laboratories of Parke, Davis and Company. 
These workers obtained on a commercial scale a pressor substance, 
beta-hypophamine, vasopressin or pitressin, and a substance acting upon 
uterine muscle, alpha-hypophamine or oxytocin. 
The pressor substance has little action upon uterine muscle, but stimu- 
lates other plain muscle, raising blood pressure and provoking peristalsis. 
Harvey Cushing has noted thatin human subjects compression or destruc- 
tion of the pituitary stalk by tumours is almost invariably associated with 
low blood pressures, while histological evidence of hypersecretion 1s 
often accompanied by raised blood pressures. Cushing has described 
a pathological condition associated with basophil adenoma of the pars 
intermedia in which the cells of the latter invade the pars nervosa. He 
