S. J. Folley

66. Some Observations on Cow's Milk poor in Non-fatty Solids

1. Traces of blood serum albumin have been demonstrated in normal milk. 2. The content of blood serum albumin is increased in many of the milks which are poor in non-fatty solids and there is evidence of some correlation between low non-fatty solids and high blood serum albumin content of the milk. 3. The experimental data support a conclusion that deficiency of nonfatty solids in milk in some cases may be due to dilution of a normal secretion in the udder by a fluid of the nature of oedema fluid, i.e. to a pathological rather than a physiological condition. 4. Some evidence, which obviously needs confirmation, has been adduced indicating that the casein-nitrogen content of milk as determined by Moirs technique may be slightly too high. The accuracy of the globulin figures seems also to be open to doubt.

The Response of the Bovine Ovary to Pregnant Mares' Serum and Horse Pituitary Extract

The response of the bovine ovary to single subcutaneous injections of pregnant mares’ serum (P. M. S.) and horse pituitary extract has been studied both quantitatively and qualitatively. For the former both time-response and dose-response data were obtained, for the latter time-response data only. Quantitative changes were measured by the following ovarian indices: mean follicular diameter (M. D.); percentage of follicles M. D. ≥ 10 mm.; number of follicles M. D. ≥ 4 mm.; number of follicles M. D. ≥ 10 mm.; total follicular volume, and weight. Only the first two criteria were found to have more than a rough relationship with the duration and magnitude of the treatment given. The threshold dose of P. M. S. for quantitative effects was between 1000 and 2000 i. u. For higher doses the ovarian response was most pronounced, but there was evidence that the maximal rate of stimulation had been reached with doses of 3000-4000 i. u. For both gonadotrophins the stage of the oestrous cycle at which injections were given had no differentiating effect upon the quantitative response obtained. In particular, the total number of follicles stimulated to growth, an index that ranged widely, showed no correlation with this variable. Qualitative changes observed included multiple ovulation, anovulatory luteinization, the formation of abnormally small corpora lutea (P. M. S. only), and the occurrence of haemorrhagic follicles. An effect caused by horse pituitary injections only was the rupture of a single follicle within 1-2 days of treatment (‘shock’ effect). Ovulation following treatment with P. M. S. only occurred when the injection was given in the last, or follicular, phase of the oestrous cycle. With horse pituitary injections ovulation followed treatment given at all stages of the cycle. The differences in the biological properties of these two gonadotrophic preparations have been discussed in the light of the new evidence arising from this study.

In vitro effects of prolactin and cortisone on the metabolism of rat mammary tissue

Abstract Cortisone exerted marked effects in vitro on the respiration of mammary gland slices from 20-day-pregnant rats. These effects appear to be such as would be expected if secretory changes had been initiated. On the other hand, the tissue was inert to prolactin at this stage. Conversely, the respiration of tissue taken at days 1–5 of lactation was sensitive in a similar way to prolactin in vitro but inert to cortisone.

Experiments on the use of chronic gonadotrophin (pregnancy urine extract) for the treatment of sterility in dairy cattle

1. The fertility of three sterile bulls was restored by injections of human pregnancy urine extract (P.U.). 2. Cows which failed to exhibit oestrus were treated by injections of P.U. Three out of five cows responded within 24 hours to intravenous injections of 5 c.c. P.U. (2500 rat units) and one out of four to an injection of 3 c.c. P.U. Two out of five cows responded immediately to a series of three intramuscular injections of 2 c.c. P.U. and one cow responded to a single intramuscular injection of 2 c.c. P.U. In addition four cows failed to respond immediately to four intramuscular injections of 2 c.c. P.U. 3. Evidence was obtained which shows that treatment with P.U. at the time of service increases the fertility of cows which show regular oestrus but nevertheless fail to conceive. It is believed that this condition is often due ( a ) to failure to ovulate, and ( b ) to deficiency of progesterone following ovulation. We are grateful to Prof. R. Rae and Mr K. W. C. Campbell for their co-operation. Part of this work was carried out during the tenure by one of us (H.M.S.W.) of a Research Grant from the Ministry of Agriculture and Fisheries.

Studies on the Absorption of Subcutaneously Implanted Tablets of Hexoestrol

1. The large compressed tablets of pure hexoestrol used, possess a ‘labile’ component (that may or may not be located in the surface zone), which is quickly lost on subcutaneous implantation or incubation with blood plasma or water. The remaining surface is much less soluble. 2. Tablets implanted subcutaneously after having suffered loss of the ‘labile’ component, because of previous in vivo implantation or incubation with blood plasma or water, undergo less absorption in a given time than unused tablets. 3. In consequence of (1), absorption curves for 1000, 500 and 250 mg. tablets in the bovine, goat, rabbit, guinea-pig, rat and pigeon show two phases, an initial phase of rapid absorption due to the loss of the ‘labile’ component, after which the curves bend sharply and thereafter pursue a linear course (linear phase). On the other hand, curves for 50, 25 and 15 mg. tablets in the rat are linear and pass through or very near the origin. 4. During the implantation period, hexoestrol tablets (and also tablets of steroid hormones) become infiltrated with structures (ghosts) composed of insoluble protein, probably a scleroprotein, formed by reaction between the hormone and soluble protein present in the tissue fluids. Ghosts are quite distinct from the fibrous-connective tissue capsules which are often formed round tablets in vivo. 5. Ghosts are also formed in hexoestrol tablets immersed in blood serum or plasma and protein solutions. 6 . Absorption values (apparent), determined by losses in weight during implantation, are in each case lower than the true value by the weight of the ghost and, on extrapolation, true absorption curves make larger intercepts on the vertical axis than apparent curves. 7. In consequence of (6) the curves for small tablets in rats are in reality of the same form as those for larger tablets, though here the difference made by the ghost correction is small. Such curves, when corrected for ghost formation, thus make only small intercepts on the vertical axis indicating that the ‘labile’ component is much less important in the small tablets than in the 250, 500 and 1000 mg. classes. 8. The absorption rate during the linear phase is the characteristic absorption rate for any given weight class of tablet. Absorption rates per mm. 2 for tablets of various sizes in different animals are approximately constant, provided the tablets are not too big in relation to the size of the animal, showing that absorption rate is proportional to surface area. With large tablets in the rat, absorption (linear phase) is either very reduced or non-existent. This may be due to saturation of the body with hexoestrol absorbed during the initial phase. 9. The effect, if any, of ghost formation on the linear absorption rate remains obscure.